diff --git a/build.ts b/build.ts
index a3fe2c8..2756794 100644
--- a/build.ts
+++ b/build.ts
@@ -35,9 +35,11 @@ async function buildBlog(): Promise<void> {
 
   const rawEntryList = await getEntryList<BlogEntryFull>(BLOG_FOLDER, `${MARKDOWN_BASE_URL_PLACEHOLDER}/blog/`);
   const entryList = applyBlogDefaults(rawEntryList);
+  // Copy + optimize images first: this rewrites header/html references to WebP in
+  // place, so the light list.json (written afterwards) references the WebP too.
+  await copyEntriesToDist(entryList, BLOG_FOLDER, blogDist);
   const blogListLight = makeLightBlogList(entryList);
   await writeJson(path.join(blogDist, LIST_FILE), blogListLight);
-  await copyEntriesToDist(entryList, BLOG_FOLDER, blogDist);
   console.log(`Blog: ${entryList.length} entries processed`);
 }
 
@@ -52,9 +54,9 @@ async function buildMaterial(): Promise<void> {
   await mkdirp(materialDist);
 
   const materialList = await getEntryList<MaterialEntry>(MATERIAL_FOLDER, `${MARKDOWN_BASE_URL_PLACEHOLDER}/material/`);
+  await copyEntriesToDist(materialList, MATERIAL_FOLDER, materialDist);
   const materialListLight = makeLightList(materialList);
   await writeJson(path.join(materialDist, LIST_FILE), materialListLight);
-  await copyEntriesToDist(materialList, MATERIAL_FOLDER, materialDist);
   console.log(`Material: ${materialList.length} entries processed`);
 }
 
diff --git a/package-lock.json b/package-lock.json
index 2eaa043..e44c8df 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -16,7 +16,8 @@
         "js-yaml": "^4.1.0",
         "marked": "^17.0.1",
         "marked-highlight": "^2.2.3",
-        "node-emoji": "^2.1.3"
+        "node-emoji": "^2.1.3",
+        "sharp": "^0.35.3"
       },
       "devDependencies": {
         "@types/fs-extra": "^11.0.4",
@@ -31,6 +32,16 @@
         "@rollup/rollup-linux-x64-gnu": "^4.57.1"
       }
     },
+    "node_modules/@emnapi/runtime": {
+      "version": "1.11.2",
+      "resolved": "https://registry.npmjs.org/@emnapi/runtime/-/runtime-1.11.2.tgz",
+      "integrity": "sha512-kyOl3X0DuTiT1h2ft8r2fYO8JYtU9a9Xis/zBSiGArNaagCOWx90N1k2wxp18czFDH+OgcWGb5ZP/XMt3dcyPA==",
+      "license": "MIT",
+      "optional": true,
+      "dependencies": {
+        "tslib": "^2.4.0"
+      }
+    },
     "node_modules/@esbuild/aix-ppc64": {
       "version": "0.27.2",
       "resolved": "https://registry.npmjs.org/@esbuild/aix-ppc64/-/aix-ppc64-0.27.2.tgz",
@@ -473,6 +484,554 @@
         "node": ">=18"
       }
     },
+    "node_modules/@img/colour": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/@img/colour/-/colour-1.1.0.tgz",
+      "integrity": "sha512-Td76q7j57o/tLVdgS746cYARfSyxk8iEfRxewL9h4OMzYhbW4TAcppl0mT4eyqXddh6L/jwoM75mo7ixa/pCeQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/@img/sharp-darwin-arm64": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-darwin-arm64/-/sharp-darwin-arm64-0.35.3.tgz",
+      "integrity": "sha512-RMnFX7YQsMoh7lWfcM4NEHHymBX/rLuKNPVM84XE9ONPcaSCDgE7CHIHpSgPcO2xcRthgBy1HfNO319mwhIAkg==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "Apache-2.0",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-libvips-darwin-arm64": "1.3.2"
+      }
+    },
+    "node_modules/@img/sharp-darwin-x64": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-darwin-x64/-/sharp-darwin-x64-0.35.3.tgz",
+      "integrity": "sha512-Xo+5uFBtLN0BKqieTxiFzFPQAUlBbbH5iBKyRX/z1JrbnYsHTfKJnUfL8+p2TPXr1pXqao4eeL4Rl144uDpK9w==",
+      "cpu": [
+        "x64"
+      ],
+      "license": "Apache-2.0",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-libvips-darwin-x64": "1.3.2"
+      }
+    },
+    "node_modules/@img/sharp-freebsd-wasm32": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-freebsd-wasm32/-/sharp-freebsd-wasm32-0.35.3.tgz",
+      "integrity": "sha512-lUxcqWIj2wMQ9BrwNjngcr1gWUr5xgaGThBRqPPalIC2n67Cqj1uPh8NnA/ZhAg8hUbKl+kVHKwgUIwe6ZYPrg==",
+      "license": "Apache-2.0",
+      "optional": true,
+      "os": [
+        "freebsd"
+      ],
+      "dependencies": {
+        "@img/sharp-wasm32": "0.35.3"
+      },
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-libvips-darwin-arm64": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@img/sharp-libvips-darwin-arm64/-/sharp-libvips-darwin-arm64-1.3.2.tgz",
+      "integrity": "sha512-9J6ypZFpQBj4YnePGoq/S38w6nz+vqg5WZLrLGY4YuSemdMq47GMLBPO42MzwdGwpg/agZ7xzZcFHa48xlywfg==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-libvips-darwin-x64": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@img/sharp-libvips-darwin-x64/-/sharp-libvips-darwin-x64-1.3.2.tgz",
+      "integrity": "sha512-m2pW1n6cns9VaubNwsZ+c3CRYjxNQWgJ5gPlnL1nbBcpkBvFm6SCFN5o0psFHI8w9n11NKhFkeEDns98tiqbEw==",
+      "cpu": [
+        "x64"
+      ],
+      "license": "LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-libvips-linux-arm": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@img/sharp-libvips-linux-arm/-/sharp-libvips-linux-arm-1.3.2.tgz",
+      "integrity": "sha512-1eMLzy92I4J6rmi4mAT8yC3HxOtniyGELlzGbNMLLeqe052ahFQ0h6LFq+lh5DsDIdYViIDst08abvSbcEdLXQ==",
+      "cpu": [
+        "arm"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-libvips-linux-arm64": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@img/sharp-libvips-linux-arm64/-/sharp-libvips-linux-arm64-1.3.2.tgz",
+      "integrity": "sha512-dqVSFynCox4C/J8kT16V7SIFAns0IjgLwkvYT7p8LQVmJ5OS5b6tI9IGflxTeuBS//zXeFIUbwt5dwxyZ17cnA==",
+      "cpu": [
+        "arm64"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-libvips-linux-ppc64": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@img/sharp-libvips-linux-ppc64/-/sharp-libvips-linux-ppc64-1.3.2.tgz",
+      "integrity": "sha512-3z0NHDxD6n5I9gc05U1eW1AyRm+Gznzq3naMrthPNqE6oYykcogW0l/jfpJdjYnuNl8R7yI9pNbE1XiUeyq0Aw==",
+      "cpu": [
+        "ppc64"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-libvips-linux-riscv64": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@img/sharp-libvips-linux-riscv64/-/sharp-libvips-linux-riscv64-1.3.2.tgz",
+      "integrity": "sha512-bsb4rI+NldGOsXuej2r8OdSS8+zXDVaCWxyWrcv6kneTOlgAHtZABRzBBCwdsPiD90J4myNJuHpg6kA20ImW/w==",
+      "cpu": [
+        "riscv64"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-libvips-linux-s390x": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@img/sharp-libvips-linux-s390x/-/sharp-libvips-linux-s390x-1.3.2.tgz",
+      "integrity": "sha512-/ABshyj8gCpyIrNXnHn4LorDJ0HHm1VhXPBlxZ8zAtfVPAaSafXPGn+sUSIRiwaSBy0mmFjSjiXI5mkcwdChKQ==",
+      "cpu": [
+        "s390x"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-libvips-linux-x64": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@img/sharp-libvips-linux-x64/-/sharp-libvips-linux-x64-1.3.2.tgz",
+      "integrity": "sha512-ITPEtgffGJ0S6G9dRyw/366tJQqFRcHWPHhC+Stpg3Z8AEMrDrTr2lhdz4f/Y/HMbRh//7Z5mBzEpVdi62Oc3w==",
+      "cpu": [
+        "x64"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-libvips-linuxmusl-arm64": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@img/sharp-libvips-linuxmusl-arm64/-/sharp-libvips-linuxmusl-arm64-1.3.2.tgz",
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+      "cpu": [
+        "arm64"
+      ],
+      "libc": [
+        "musl"
+      ],
+      "license": "LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-libvips-linuxmusl-x64": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@img/sharp-libvips-linuxmusl-x64/-/sharp-libvips-linuxmusl-x64-1.3.2.tgz",
+      "integrity": "sha512-m0lrLiUt+lBYnCFr8qV/65yMR4E/c7/wf78I5eKTdkEakFAlZ9QlzEM3QIhhAwVeUhLAHLcCq7a7Vszq/oFNZQ==",
+      "cpu": [
+        "x64"
+      ],
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+        "musl"
+      ],
+      "license": "LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-linux-arm": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-linux-arm/-/sharp-linux-arm-0.35.3.tgz",
+      "integrity": "sha512-affVWCTLooy8TSxbDx2qkzuDeaWLNVBA+P//FNBirHsXpP2fuBhk5AuboYUnrDnzoXes8GFjpTx0SBFOCRg+FA==",
+      "cpu": [
+        "arm"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "Apache-2.0",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-libvips-linux-arm": "1.3.2"
+      }
+    },
+    "node_modules/@img/sharp-linux-arm64": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-linux-arm64/-/sharp-linux-arm64-0.35.3.tgz",
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+      "cpu": [
+        "arm64"
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+        "glibc"
+      ],
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+      "optional": true,
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+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-libvips-linux-arm64": "1.3.2"
+      }
+    },
+    "node_modules/@img/sharp-linux-ppc64": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-linux-ppc64/-/sharp-linux-ppc64-0.35.3.tgz",
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+      "cpu": [
+        "ppc64"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "Apache-2.0",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-libvips-linux-ppc64": "1.3.2"
+      }
+    },
+    "node_modules/@img/sharp-linux-riscv64": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-linux-riscv64/-/sharp-linux-riscv64-0.35.3.tgz",
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+        "riscv64"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "Apache-2.0",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-libvips-linux-riscv64": "1.3.2"
+      }
+    },
+    "node_modules/@img/sharp-linux-s390x": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-linux-s390x/-/sharp-linux-s390x-0.35.3.tgz",
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+      "cpu": [
+        "s390x"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "Apache-2.0",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-libvips-linux-s390x": "1.3.2"
+      }
+    },
+    "node_modules/@img/sharp-linux-x64": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-linux-x64/-/sharp-linux-x64-0.35.3.tgz",
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+      "cpu": [
+        "x64"
+      ],
+      "libc": [
+        "glibc"
+      ],
+      "license": "Apache-2.0",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-libvips-linux-x64": "1.3.2"
+      }
+    },
+    "node_modules/@img/sharp-linuxmusl-arm64": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-linuxmusl-arm64/-/sharp-linuxmusl-arm64-0.35.3.tgz",
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+        "arm64"
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+        "musl"
+      ],
+      "license": "Apache-2.0",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-libvips-linuxmusl-arm64": "1.3.2"
+      }
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+    "node_modules/@img/sharp-linuxmusl-x64": {
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+      "resolved": "https://registry.npmjs.org/@img/sharp-linuxmusl-x64/-/sharp-linuxmusl-x64-0.35.3.tgz",
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+        "x64"
+      ],
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+        "musl"
+      ],
+      "license": "Apache-2.0",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-libvips-linuxmusl-x64": "1.3.2"
+      }
+    },
+    "node_modules/@img/sharp-wasm32": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-wasm32/-/sharp-wasm32-0.35.3.tgz",
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+      "optional": true,
+      "dependencies": {
+        "@emnapi/runtime": "^1.11.1"
+      },
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+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-webcontainers-wasm32": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-webcontainers-wasm32/-/sharp-webcontainers-wasm32-0.35.3.tgz",
+      "integrity": "sha512-2rnq7bX3NzeR2T4YWgz8qiG4h3TSdMe+vN1iQXpJleSJ3SM5zQ8Fy2SyyXAWlbxpEZ2Y+Z4u1BePgJEYbSy80Q==",
+      "cpu": [
+        "wasm32"
+      ],
+      "license": "Apache-2.0",
+      "optional": true,
+      "dependencies": {
+        "@img/sharp-wasm32": "0.35.3"
+      },
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-win32-arm64": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-win32-arm64/-/sharp-win32-arm64-0.35.3.tgz",
+      "integrity": "sha512-4bPwFdMbeC4JQ8L8LOyWp6nsHcboP5fxkp6iPOXz2Vg49R42TuMs2whkJ5OAP4/Ul035qOzy0AecOF9VOscn4w==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "Apache-2.0 AND LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "win32"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-win32-ia32": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-win32-ia32/-/sharp-win32-ia32-0.35.3.tgz",
+      "integrity": "sha512-r53mXsBN6lFUDiST764SvgwUdHAqM4rPAiDzAmf4fLoB6X/rkfyTrLCg6+g17wJJiCmB3JYgHuUldCWUIRFSXw==",
+      "cpu": [
+        "ia32"
+      ],
+      "license": "Apache-2.0 AND LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "win32"
+      ],
+      "engines": {
+        "node": "^20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
+    "node_modules/@img/sharp-win32-x64": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/@img/sharp-win32-x64/-/sharp-win32-x64-0.35.3.tgz",
+      "integrity": "sha512-D4y1vNeZrIIJCN+uHaWVtH86B+aCrdMYYjicy9pXHvbGZeGYLLSd3wdVuC37FxVXlU1ARsk84eKWfWMXGYEqvA==",
+      "cpu": [
+        "x64"
+      ],
+      "license": "Apache-2.0 AND LGPL-3.0-or-later",
+      "optional": true,
+      "os": [
+        "win32"
+      ],
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      }
+    },
     "node_modules/@jridgewell/sourcemap-codec": {
       "version": "1.5.5",
       "resolved": "https://registry.npmjs.org/@jridgewell/sourcemap-codec/-/sourcemap-codec-1.5.5.tgz",
@@ -1213,6 +1772,15 @@
         }
       }
     },
+    "node_modules/detect-libc": {
+      "version": "2.1.2",
+      "resolved": "https://registry.npmjs.org/detect-libc/-/detect-libc-2.1.2.tgz",
+      "integrity": "sha512-Btj2BOOO83o3WyH59e8MgXsxEQVcarkUOpEYrubB0urwnN10yQ364rsiByU11nZlqWYZm05i/of7io4mzihBtQ==",
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">=8"
+      }
+    },
     "node_modules/emojilib": {
       "version": "2.4.0",
       "resolved": "https://registry.npmjs.org/emojilib/-/emojilib-2.4.0.tgz",
@@ -1774,10 +2342,9 @@
       }
     },
     "node_modules/semver": {
-      "version": "7.7.3",
-      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.3.tgz",
-      "integrity": "sha512-SdsKMrI9TdgjdweUSR9MweHA4EJ8YxHn8DFaDisvhVlUOe4BF1tLD7GAj0lIqWVl+dPb/rExr0Btby5loQm20Q==",
-      "dev": true,
+      "version": "7.8.5",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.8.5.tgz",
+      "integrity": "sha512-Y7/KDsb8LjooZpwaqGyulO6DQlksgCncchHGk+sZIY4SBvUocMBEFH5Ur1fI4dV+Jvl0w6cjvucaIi40puRioA==",
       "license": "ISC",
       "bin": {
         "semver": "bin/semver.js"
@@ -1786,6 +2353,55 @@
         "node": ">=10"
       }
     },
+    "node_modules/sharp": {
+      "version": "0.35.3",
+      "resolved": "https://registry.npmjs.org/sharp/-/sharp-0.35.3.tgz",
+      "integrity": "sha512-ej0zVHuZGHCiABXcNxeYhpRnPNPAcvbG8RMdBAhDAxLKkCRVSpK3Iyu7qbqw3JMzoj0REeM6f3tJLtVwl0023Q==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@img/colour": "^1.1.0",
+        "detect-libc": "^2.1.2",
+        "semver": "^7.8.5"
+      },
+      "engines": {
+        "node": ">=20.9.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/libvips"
+      },
+      "optionalDependencies": {
+        "@img/sharp-darwin-arm64": "0.35.3",
+        "@img/sharp-darwin-x64": "0.35.3",
+        "@img/sharp-freebsd-wasm32": "0.35.3",
+        "@img/sharp-libvips-darwin-arm64": "1.3.2",
+        "@img/sharp-libvips-darwin-x64": "1.3.2",
+        "@img/sharp-libvips-linux-arm": "1.3.2",
+        "@img/sharp-libvips-linux-arm64": "1.3.2",
+        "@img/sharp-libvips-linux-ppc64": "1.3.2",
+        "@img/sharp-libvips-linux-riscv64": "1.3.2",
+        "@img/sharp-libvips-linux-s390x": "1.3.2",
+        "@img/sharp-libvips-linux-x64": "1.3.2",
+        "@img/sharp-libvips-linuxmusl-arm64": "1.3.2",
+        "@img/sharp-libvips-linuxmusl-x64": "1.3.2",
+        "@img/sharp-linux-arm": "0.35.3",
+        "@img/sharp-linux-arm64": "0.35.3",
+        "@img/sharp-linux-ppc64": "0.35.3",
+        "@img/sharp-linux-riscv64": "0.35.3",
+        "@img/sharp-linux-s390x": "0.35.3",
+        "@img/sharp-linux-x64": "0.35.3",
+        "@img/sharp-linuxmusl-arm64": "0.35.3",
+        "@img/sharp-linuxmusl-x64": "0.35.3",
+        "@img/sharp-webcontainers-wasm32": "0.35.3",
+        "@img/sharp-win32-arm64": "0.35.3",
+        "@img/sharp-win32-ia32": "0.35.3",
+        "@img/sharp-win32-x64": "0.35.3"
+      },
+      "peerDependenciesMeta": {
+        "@types/node": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/siginfo": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/siginfo/-/siginfo-2.0.0.tgz",
@@ -1922,6 +2538,13 @@
         "nodetouch": "bin/nodetouch.js"
       }
     },
+    "node_modules/tslib": {
+      "version": "2.8.1",
+      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.8.1.tgz",
+      "integrity": "sha512-oJFu94HQb+KVduSUQL7wnpmqnfmLsOA/nAh6b6EH0wCEoK0/mPeXU6c3wKDV83MkOuHPRHtSXKKU99IBazS/2w==",
+      "license": "0BSD",
+      "optional": true
+    },
     "node_modules/tsx": {
       "version": "4.21.0",
       "resolved": "https://registry.npmjs.org/tsx/-/tsx-4.21.0.tgz",
diff --git a/package.json b/package.json
index c87617e..a064e11 100644
--- a/package.json
+++ b/package.json
@@ -13,13 +13,14 @@
   "description": "",
   "dependencies": {
     "fs-extra": "^11.2.0",
+    "github-slugger": "^2.0.0",
     "highlight.js": "^11.10.0",
     "image-size": "^2.0.2",
     "js-yaml": "^4.1.0",
-    "github-slugger": "^2.0.0",
     "marked": "^17.0.1",
     "marked-highlight": "^2.2.3",
-    "node-emoji": "^2.1.3"
+    "node-emoji": "^2.1.3",
+    "sharp": "^0.35.3"
   },
   "optionalDependencies": {
     "@rollup/rollup-darwin-arm64": "^4.57.1",
diff --git a/shared/base.utils.spec.ts b/shared/base.utils.spec.ts
index b9ad2d9..27a7245 100644
--- a/shared/base.utils.spec.ts
+++ b/shared/base.utils.spec.ts
@@ -1,4 +1,5 @@
 import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import sharp from 'sharp';
 import { readMarkdownFile, readFolders, getImageDimensions, copyEntriesToDist, getEntryList, markdownToEntry } from './base.utils';
 import { EntryBase } from './base.types';
 import * as fs from 'fs/promises';
@@ -124,30 +125,39 @@ describe('base.utils', () => {
       await fs.rm(testDir, { recursive: true, force: true });
     });
 
-    it('should copy entry folder to dist and create entry.json', async () => {
-      // Create source entry
+    it('should copy entry, optimize images to webp, and rewrite references', async () => {
+      // Create source entry with a real PNG (sharp needs a valid image).
       const entrySlug = 'test-post';
       await fs.mkdir(path.join(sourceDir, entrySlug));
       await fs.writeFile(path.join(sourceDir, entrySlug, 'README.md'), '# Test');
-      await fs.writeFile(path.join(sourceDir, entrySlug, 'image.png'), 'fake-image');
-
-      const entries = [{ slug: entrySlug, html: '<p>Test</p>', meta: { title: 'Test' } }];
+      await sharp({ create: { width: 120, height: 80, channels: 3, background: { r: 10, g: 20, b: 30 } } })
+        .png()
+        .toFile(path.join(sourceDir, entrySlug, 'image.png'));
+
+      const entries = [{
+        slug: entrySlug,
+        html: '<p><img src="%%URL%%/blog/test-post/image.png"></p>',
+        meta: { title: 'Test', header: { url: 'image.png', width: 120, height: 80 } },
+      }];
       await copyEntriesToDist(entries, sourceDir, distDir);
 
-      // Check entry.json was created
+      // entry.json created; html + header references rewritten to webp
       const entryJson = JSON.parse(
         await fs.readFile(path.join(distDir, entrySlug, 'entry.json'), 'utf8')
       );
       expect(entryJson.slug).toBe(entrySlug);
-      expect(entryJson.html).toBe('<p>Test</p>');
-
-      // Check README.md was removed
-      await expect(fs.access(path.join(distDir, entrySlug, 'README.md')))
-        .rejects.toThrow();
-
-      // Check other files were copied
-      const imageContent = await fs.readFile(path.join(distDir, entrySlug, 'image.png'), 'utf8');
-      expect(imageContent).toBe('fake-image');
+      expect(entryJson.html).toContain('image.webp');
+      expect(entryJson.html).not.toContain('image.png');
+      expect(entryJson.meta.header.url).toBe('image.webp');
+      expect(entryJson.meta.header.width).toBe(120);
+      expect(entryJson.meta.header.height).toBe(80);
+
+      // README.md removed
+      await expect(fs.access(path.join(distDir, entrySlug, 'README.md'))).rejects.toThrow();
+
+      // webp generated, original png removed
+      await expect(fs.access(path.join(distDir, entrySlug, 'image.webp'))).resolves.toBeUndefined();
+      await expect(fs.access(path.join(distDir, entrySlug, 'image.png'))).rejects.toThrow();
     });
 
     it('should handle multiple entries', async () => {
diff --git a/shared/base.utils.ts b/shared/base.utils.ts
index ba44b72..7255241 100644
--- a/shared/base.utils.ts
+++ b/shared/base.utils.ts
@@ -7,6 +7,7 @@ import { copy, remove, writeJson, mkdirp } from 'fs-extra';
 import { JekyllMarkdownParser } from './jekyll-markdown-parser';
 import { EntryBase, ImageDimensions } from './base.types';
 import { registerAnchors, registerHtmlAnchors, registerLinks } from './link-validator';
+import { optimizeImagesInFolder, rewriteImageReferences } from './image-optimizer';
 
 const README_FILE = 'README.md';
 const ENTRY_FILE = 'entry.json';
@@ -34,11 +35,17 @@ export async function getImageDimensions(imagePath: string): Promise<ImageDimens
   return { width, height };
 }
 
-/** Copy folder entries to dist, remove source file, and write entry.json */
+/**
+ * Copy folder entries to dist, optimize their images to WebP, remove the README,
+ * and write entry.json.
+ *
+ * Image optimization mutates `entry.meta.header` (url + dimensions) and `entry.html`
+ * in place, so a `list.json` generated AFTER this call reflects the WebP references.
+ */
 export async function copyEntriesToDist<T extends { slug: string }>(
   entries: T[],
   sourceFolder: string,
-  distFolder: string
+  distFolder: string,
 ): Promise<void> {
   // Process sequentially to fail fast on first error
   for (const entry of entries) {
@@ -48,6 +55,10 @@ export async function copyEntriesToDist<T extends { slug: string }>(
     await copy(path.join(sourceFolder, entry.slug), entryDistFolder);
     await remove(path.join(entryDistFolder, README_FILE));
 
+    // jpg/png → resized WebP (in dist); rewrite header + html references to it.
+    const optimized = await optimizeImagesInFolder(entryDistFolder);
+    rewriteImageReferences(entry as { html?: unknown; meta?: unknown }, optimized);
+
     const entryJsonPath = path.join(entryDistFolder, ENTRY_FILE);
     await writeJson(entryJsonPath, entry);
     console.log('Generated post file:', entryJsonPath);
diff --git a/shared/image-optimizer.spec.ts b/shared/image-optimizer.spec.ts
new file mode 100644
index 0000000..2bf0102
--- /dev/null
+++ b/shared/image-optimizer.spec.ts
@@ -0,0 +1,80 @@
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import sharp from 'sharp';
+import * as fs from 'fs/promises';
+import * as path from 'path';
+import { optimizeImagesInFolder, rewriteImageReferences, MAX_WIDTH } from './image-optimizer';
+
+describe('image-optimizer', () => {
+  const dir = '/tmp/test-img-opt-' + Date.now();
+
+  beforeEach(async () => {
+    await fs.mkdir(dir, { recursive: true });
+  });
+  afterEach(async () => {
+    await fs.rm(dir, { recursive: true, force: true });
+  });
+
+  describe('optimizeImagesInFolder', () => {
+    it('converts jpg/png to webp, downscales wide images, removes originals', async () => {
+      await sharp({ create: { width: 2000, height: 800, channels: 3, background: '#123456' } })
+        .jpeg()
+        .toFile(path.join(dir, 'big.jpg'));
+      await sharp({ create: { width: 100, height: 100, channels: 3, background: '#abcdef' } })
+        .png()
+        .toFile(path.join(dir, 'small.png'));
+      // Image in a subfolder (recursion).
+      await fs.mkdir(path.join(dir, 'gallery'), { recursive: true });
+      await sharp({ create: { width: 300, height: 200, channels: 3, background: '#00ff00' } })
+        .jpeg()
+        .toFile(path.join(dir, 'gallery', 'shot.jpg'));
+      await fs.writeFile(path.join(dir, 'logo.svg'), '<svg></svg>');
+
+      const map = await optimizeImagesInFolder(dir);
+
+      // Wide image downscaled to MAX_WIDTH, small one not upscaled.
+      expect(map.get('big.jpg')?.webp).toBe('big.webp');
+      expect(map.get('big.jpg')?.width).toBe(MAX_WIDTH);
+      expect(map.get('small.png')?.webp).toBe('small.webp');
+      expect(map.get('small.png')?.width).toBe(100);
+
+      // Subfolder image converted too (recursive), keyed by relative path.
+      expect(map.get(path.join('gallery', 'shot.jpg'))?.webp).toBe(path.join('gallery', 'shot.webp'));
+      await expect(fs.access(path.join(dir, 'gallery', 'shot.webp'))).resolves.toBeUndefined();
+      await expect(fs.access(path.join(dir, 'gallery', 'shot.jpg'))).rejects.toThrow();
+
+      // Originals removed, webp present.
+      await expect(fs.access(path.join(dir, 'big.jpg'))).rejects.toThrow();
+      await expect(fs.access(path.join(dir, 'big.webp'))).resolves.toBeUndefined();
+      await expect(fs.access(path.join(dir, 'small.webp'))).resolves.toBeUndefined();
+
+      // SVG untouched and not in the map.
+      await expect(fs.access(path.join(dir, 'logo.svg'))).resolves.toBeUndefined();
+      expect(map.has('logo.svg')).toBe(false);
+    });
+
+    it('returns an empty map when there is nothing to optimize', async () => {
+      await fs.writeFile(path.join(dir, 'notes.txt'), 'hello');
+      const map = await optimizeImagesInFolder(dir);
+      expect(map.size).toBe(0);
+    });
+  });
+
+  describe('rewriteImageReferences', () => {
+    it('rewrites header (url + dimensions) and html references, leaving others alone', () => {
+      const map = new Map([['header.jpg', { webp: 'header.webp', width: 800, height: 400 }]]);
+      const entry = {
+        html: '<img src="x/header.jpg"> und <img src="x/other.svg">',
+        meta: { header: { url: 'header.jpg', width: 2000, height: 1000 } },
+      };
+
+      rewriteImageReferences(entry, map);
+
+      expect(entry.meta.header.url).toBe('header.webp');
+      expect(entry.meta.header.width).toBe(800);
+      expect(entry.meta.header.height).toBe(400);
+      expect(entry.html).toContain('header.webp');
+      expect(entry.html).not.toContain('header.jpg');
+      expect(entry.html).toContain('other.svg');
+    });
+  });
+});
diff --git a/shared/image-optimizer.ts b/shared/image-optimizer.ts
new file mode 100644
index 0000000..76d7d34
--- /dev/null
+++ b/shared/image-optimizer.ts
@@ -0,0 +1,112 @@
+import * as path from 'path';
+import { readdir, unlink } from 'fs/promises';
+import sharp from 'sharp';
+
+/**
+ * Image optimization for article assets.
+ *
+ * Raster images (jpg/jpeg/png) in an entry folder are converted to resized WebP.
+ * The original files are removed from the dist folder, so the CDN only serves the
+ * optimized variant. SVG, GIF and existing WebP files are left untouched.
+ *
+ * Every consuming website (angular.schule, angular-buch.com, agentic.schule, …)
+ * benefits automatically, because they all read the same generated JSON/images.
+ */
+
+/** Max width in px; larger images are downscaled (never upscaled). */
+export const MAX_WIDTH = 1600;
+/** WebP quality (0-100). */
+export const WEBP_QUALITY = 80;
+
+const RASTER = /\.(jpe?g|png)$/i;
+
+export interface OptimizedImage {
+  /** New relative path, e.g. "header.webp" or "gallery/shot.webp" */
+  webp: string;
+  /** Dimensions of the generated WebP (after optional downscaling). */
+  width: number;
+  height: number;
+}
+
+/** Collect all file paths under `dir`, relative to `base` (recursive). */
+async function collectFiles(dir: string, base: string): Promise<string[]> {
+  const dirents = await readdir(dir, { withFileTypes: true });
+  const files: string[] = [];
+  for (const dirent of dirents) {
+    const full = path.join(dir, dirent.name);
+    if (dirent.isDirectory()) {
+      files.push(...(await collectFiles(full, base)));
+    } else {
+      files.push(path.relative(base, full));
+    }
+  }
+  return files;
+}
+
+/**
+ * Convert all jpg/jpeg/png files in `folder` (recursively, incl. subfolders like
+ * `.../gallery/shot.jpg`) to resized WebP in place, deleting the originals.
+ * Returns a map: original relative path → optimized info. Empty when nothing to do.
+ */
+export async function optimizeImagesInFolder(
+  folder: string,
+): Promise<Map<string, OptimizedImage>> {
+  const optimized = new Map<string, OptimizedImage>();
+  const files = await collectFiles(folder, folder);
+
+  for (const rel of files) {
+    if (!RASTER.test(rel)) continue;
+
+    const source = path.join(folder, rel);
+    const webpRel = rel.replace(RASTER, '.webp');
+    const target = path.join(folder, webpRel);
+
+    const info = await sharp(source)
+      .rotate() // respektiert EXIF-Orientierung
+      .resize({ width: MAX_WIDTH, withoutEnlargement: true })
+      .webp({ quality: WEBP_QUALITY })
+      .toFile(target);
+
+    optimized.set(rel, { webp: webpRel, width: info.width, height: info.height });
+    await unlink(source);
+  }
+
+  return optimized;
+}
+
+/**
+ * Rewrite image references in an entry after optimization (mutates in place):
+ *  - `meta.header` (object with url/width/height) → WebP url + new dimensions
+ *  - `html` → every reference to a converted file name is pointed at the WebP
+ */
+export function rewriteImageReferences(
+  entry: { html?: unknown; meta?: unknown },
+  optimized: Map<string, OptimizedImage>,
+): void {
+  if (optimized.size === 0) return;
+
+  // Header (used by both entry.json and the light list.json).
+  const meta = entry.meta as
+    | { header?: { url?: string; width?: number; height?: number } }
+    | undefined;
+  const header = meta?.header;
+  if (header && typeof header.url === 'string') {
+    const opt = optimized.get(header.url);
+    if (opt) {
+      header.url = opt.webp;
+      header.width = opt.width;
+      header.height = opt.height;
+    }
+  }
+
+  // Content images inside the rendered HTML. Replace longer file names first so
+  // that a short name is never a partial match inside a longer one.
+  if (typeof entry.html === 'string') {
+    let html = entry.html;
+    const names = [...optimized.keys()].sort((a, b) => b.length - a.length);
+    for (const original of names) {
+      html = html.split(original).join(optimized.get(original)!.webp);
+    }
+    entry.html = html;
+  }
+}