diff --git a/lib/perron/html_processor.rb b/lib/perron/html_processor.rb
index b35c784..1c4efb0 100644
--- a/lib/perron/html_processor.rb
+++ b/lib/perron/html_processor.rb
@@ -2,6 +2,7 @@
 
 require "perron/html_processor/target_blank"
 require "perron/html_processor/lazy_load_images"
+require "perron/html_processor/absolute_urls"
 
 module Perron
   class HtmlProcessor
@@ -21,7 +22,8 @@ def process
 
     BUILT_IN = {
       "target_blank" => Perron::HtmlProcessor::TargetBlank,
-      "lazy_load_images" => Perron::HtmlProcessor::LazyLoadImages
+      "lazy_load_images" => Perron::HtmlProcessor::LazyLoadImages,
+      "absolute_urls" => Perron::HtmlProcessor::AbsoluteUrls
     }.tap do |processors|
       require "rouge"
       require "perron/html_processor/syntax_highlight"
diff --git a/lib/perron/html_processor/absolute_urls.rb b/lib/perron/html_processor/absolute_urls.rb
new file mode 100644
index 0000000..6ce4c0f
--- /dev/null
+++ b/lib/perron/html_processor/absolute_urls.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module Perron
+  class HtmlProcessor
+    class AbsoluteUrls < HtmlProcessor::Base
+      def process
+        @html.css("img").each do |image|
+          src = image["src"]
+
+          next if src.blank? || absolute_url?(src)
+
+          image["src"] = base_url + src
+        end
+      end
+
+      private
+
+      def absolute_url?(src)
+        src.start_with?("http://", "https://", "//")
+      end
+
+      def base_url
+        Perron.configuration.url.delete_suffix("/")
+      end
+    end
+  end
+end
diff --git a/lib/perron/resource/metadata.rb b/lib/perron/resource/metadata.rb
index b501b99..1723476 100644
--- a/lib/perron/resource/metadata.rb
+++ b/lib/perron/resource/metadata.rb
@@ -25,6 +25,8 @@ def apply_fallbacks_and_defaults(to:)
 
         to[:canonical_url] ||= canonical_url
 
+        to[:image] = absolute_url(to[:image]) if to[:image]
+
         to[:og_image] ||= to[:image]
         to[:twitter_image] ||= to[:og_image]
 
@@ -52,13 +54,20 @@ def canonical_url
         begin
           Rails.application.routes.url_helpers.polymorphic_url(
             @resource,
-          **Perron.configuration.default_url_options
+            **Perron.configuration.default_url_options
           )
         rescue
           false
         end
       end
 
+      def absolute_url(path)
+        return path if path.blank?
+        return path if path.start_with?("http://", "https://", "//")
+
+        Perron.configuration.url.delete_suffix("/") + path
+      end
+
       def site_data
         @config.metadata.except(:title_separator, :title_suffix).deep_symbolize_keys || {}
       end
diff --git a/lib/perron/site/builder/feeds/atom.erb b/lib/perron/site/builder/feeds/atom.erb
index 66e7c65..a54332b 100644
--- a/lib/perron/site/builder/feeds/atom.erb
+++ b/lib/perron/site/builder/feeds/atom.erb
@@ -31,9 +31,9 @@
 
     <% base_url = url_for_resource(resource) %>
     <% if base_url %>
-      <content type="html" xml:base="<%= base_url %>"><![CDATA[<%= Perron::Markdown.render(resource.content) %>]]></content>
+      <content type="html" xml:base="<%= base_url %>"><![CDATA[<%= Perron::Markdown.render(resource.content, processors: ["absolute_urls"]) %>]]></content>
     <% else %>
-      <content type="html"><![CDATA[<%= Perron::Markdown.render(resource.content) %>]]></content>
+      <content type="html"><![CDATA[<%= Perron::Markdown.render(resource.content, processors: ["absolute_urls"]) %>]]></content>
     <% end %>
 
     <% resource.metadata.tags&.each do |tag| %>
diff --git a/lib/perron/site/builder/feeds/json.erb b/lib/perron/site/builder/feeds/json.erb
index be8dac8..142fb38 100644
--- a/lib/perron/site/builder/feeds/json.erb
+++ b/lib/perron/site/builder/feeds/json.erb
@@ -13,7 +13,7 @@
       date_published: resource.published_at&.iso8601,
       title: resource.metadata.title,
       authors: (item_author && item_author.name ? [{ name: item_author.name, email: item_author.email, url: item_author.url, avatar: item_author.avatar }.compact] : nil),
-      content_html: Perron::Markdown.render(resource.content)
+      content_html: Perron::Markdown.render(resource.content, processors: ["absolute_urls"])
     }.compact
   }
 }.to_json %>
diff --git a/lib/perron/site/builder/feeds/rss.erb b/lib/perron/site/builder/feeds/rss.erb
index 1cdec1f..a8d1548 100644
--- a/lib/perron/site/builder/feeds/rss.erb
+++ b/lib/perron/site/builder/feeds/rss.erb
@@ -21,7 +21,7 @@
       <% end %>
       <title><%= resource.metadata.title %></title>
 
-      <description><![CDATA[<%= Perron::Markdown.render(resource.content) %>]]></description>
+      <description><![CDATA[<%= Perron::Markdown.render(resource.content, processors: ["absolute_urls"]) %>]]></description>
     </item>
     <% end %>
   </channel>
diff --git a/test/perron/html_processor/absolute_urls_test.rb b/test/perron/html_processor/absolute_urls_test.rb
new file mode 100644
index 0000000..3d8b4ef
--- /dev/null
+++ b/test/perron/html_processor/absolute_urls_test.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class Perron::HtmlProcessor::AbsoluteUrlsTest < ActionView::TestCase
+  def process_html(html)
+    document = Nokogiri::HTML::DocumentFragment.parse(html)
+
+    Perron::HtmlProcessor::AbsoluteUrls.new(document).process
+
+    document.to_html
+  end
+
+  test 'converts relative image src to absolute URL' do
+    html = '<img src="/images/photo.jpg" alt="A photo">'
+    processed = process_html(html)
+
+    assert_dom_equal '<img src="http://localhost:3000/images/photo.jpg" alt="A photo">', processed
+  end
+
+  test 'does not modify already absolute http URL' do
+    html = '<img src="http://example.com/images/photo.jpg" alt="A photo">'
+    processed = process_html(html)
+
+    assert_dom_equal html, processed
+  end
+
+  test 'does not modify already absolute https URL' do
+    html = '<img src="https://example.com/images/photo.jpg" alt="A photo">'
+    processed = process_html(html)
+
+    assert_dom_equal html, processed
+  end
+
+  test 'does not modify protocol-relative URL' do
+    html = '<img src="//example.com/images/photo.jpg" alt="A photo">'
+    processed = process_html(html)
+
+    assert_dom_equal html, processed
+  end
+
+  test 'does not modify image without src attribute' do
+    html = '<img alt="A photo">'
+    processed = process_html(html)
+
+    assert_dom_equal html, processed
+  end
+
+  test 'processes multiple images' do
+    html = '<img src="/images/photo1.jpg"><img src="/images/photo2.jpg">'
+    processed = process_html(html)
+
+    assert_dom_equal '<img src="http://localhost:3000/images/photo1.jpg"><img src="http://localhost:3000/images/photo2.jpg">',
+                     processed
+  end
+
+  test 'does not affect content without images' do
+    html = '<p>Some text, but no images.</p>'
+    processed = process_html(html)
+
+    assert_dom_equal html, processed
+  end
+end
diff --git a/test/perron/resource/metadata_test.rb b/test/perron/resource/metadata_test.rb
index 9f41579..a4093e7 100644
--- a/test/perron/resource/metadata_test.rb
+++ b/test/perron/resource/metadata_test.rb
@@ -1,80 +1,80 @@
-require "test_helper"
+require 'test_helper'
 
 class Perron::Resource::MetadataTest < ActiveSupport::TestCase
   include ConfigurationHelper
 
   def setup
-    @post = Content::Post.new("test/dummy/app/content/posts/2023-05-15-sample-post.md")
+    @post = Content::Post.new('test/dummy/app/content/posts/2023-05-15-sample-post.md')
     @post_frontmatter = Perron::Resource::Separator.new(@post.raw_content).frontmatter
-    @posts_collection = Perron::Site.collection("posts")
+    @posts_collection = Perron::Site.collection('posts')
 
-    @custom_page = Content::Page.new("test/dummy/app/content/pages/custom.md")
+    @custom_page = Content::Page.new('test/dummy/app/content/pages/custom.md')
     @custom_page_frontmatter = Perron::Resource::Separator.new(@custom_page.raw_content).frontmatter
-    @pages_collection = Perron::Site.collection("pages")
+    @pages_collection = Perron::Site.collection('pages')
 
-    @root_page = Content::Page.new("test/dummy/app/content/pages/root.erb")
+    @root_page = Content::Page.new('test/dummy/app/content/pages/root.erb')
     @root_page_frontmatter = Perron::Resource::Separator.new(@root_page.raw_content).frontmatter
 
-    @about_page = Content::Page.new("test/dummy/app/content/pages/about.md")
+    @about_page = Content::Page.new('test/dummy/app/content/pages/about.md')
     @about_page_frontmatter = Perron::Resource::Separator.new(@about_page.raw_content).frontmatter
   end
 
-  test "generates basic metadata with fallbacks for a standard blog post" do
+  test 'generates basic metadata with fallbacks for a standard blog post' do
     metadata = Perron::Resource::Metadata.new(
       resource: @post,
       frontmatter: @post_frontmatter,
       collection: @posts_collection
     ).data
 
-    assert_equal "Sample Post", metadata.title
-    assert_equal "Describing sample post", metadata.description
+    assert_equal 'Sample Post', metadata.title
+    assert_equal 'Describing sample post', metadata.description
 
-    assert_equal "http://localhost:3000/blog/sample-post/", metadata.og_url
+    assert_equal 'http://localhost:3000/blog/sample-post/', metadata.og_url
     assert_equal Date.new(2023, 5, 15).to_datetime, metadata.article_published_time
 
-    assert_equal "Dummy App", metadata.og_site_name
+    assert_equal 'Dummy App', metadata.og_site_name
 
-    assert_equal "summary_large_image", metadata.twitter_card
+    assert_equal 'summary_large_image', metadata.twitter_card
 
-    assert_equal "Sample Post", metadata.og_title
-    assert_equal "Sample Post", metadata.twitter_title
-    assert_equal "Describing sample post", metadata.og_description
-    assert_equal "Describing sample post", metadata.twitter_description
+    assert_equal 'Sample Post', metadata.og_title
+    assert_equal 'Sample Post', metadata.twitter_title
+    assert_equal 'Describing sample post', metadata.og_description
+    assert_equal 'Describing sample post', metadata.twitter_description
   end
 
-  test "frontmatter values take precedence over all defaults and fallbacks" do
+  test 'frontmatter values take precedence over all defaults and fallbacks' do
     metadata = Perron::Resource::Metadata.new(
       resource: @custom_page,
       frontmatter: @custom_page_frontmatter,
       collection: @pages_collection
     ).data
 
-    assert_equal "Custom OG Title For Sharing", metadata.title
-    assert_equal "Custom OG Title For Sharing", metadata.og_title, "og_title should be from frontmatter, not a fallback"
-    assert_equal "summary", metadata.twitter_card, "twitter_card should be from frontmatter, not the default"
+    assert_equal 'Custom OG Title For Sharing', metadata.title
+    assert_equal 'Custom OG Title For Sharing', metadata.og_title, 'og_title should be from frontmatter, not a fallback'
+    assert_equal 'summary', metadata.twitter_card, 'twitter_card should be from frontmatter, not the default'
 
-    assert_equal "/image.jpg", metadata.image
-    assert_equal "/og-image.jpg", metadata.og_image, "og_image should be from frontmatter, not a fallback from image"
-    assert_equal "/og-image.jpg", metadata.twitter_image, "twitter_image should fall back to the specific og_image"
+    assert_equal 'http://localhost:3000/image.jpg', metadata.image
+    assert_equal '/og-image.jpg', metadata.og_image, 'og_image should be from frontmatter, not a fallback from image'
+    assert_equal '/og-image.jpg', metadata.twitter_image, 'twitter_image should fall back to the specific og_image'
   end
 
-  test "inherits metadata from collection configuration" do
-    collection = Perron::Site.collection("posts")
+  test 'inherits metadata from collection configuration' do
+    collection = Perron::Site.collection('posts')
     metadata = Perron::Resource::Metadata.new(
       resource: @post,
       frontmatter: @post_frontmatter,
       collection: collection
     ).data
 
-    assert_equal "The Post Collection Team", metadata.author
-    assert_equal "The Post Collection Team", metadata.og_author, "og_author should fall back to collection author"
-    assert_equal "article", metadata.type
-    assert_equal "article", metadata.og_type, "og_type should fall back to collection type"
+    assert_equal 'The Post Collection Team', metadata.author
+    assert_equal 'The Post Collection Team', metadata.og_author, 'og_author should fall back to collection author'
+    assert_equal 'article', metadata.type
+    assert_equal 'article', metadata.og_type, 'og_type should fall back to collection type'
   end
 
-  test "inherits and merges metadata from site configuration" do
+  test 'inherits and merges metadata from site configuration' do
     Perron.configure do |config|
-      config.metadata = { author: "The Dummy App Team", locale: "en_GB", description: "Site-wide description" }
+      config.metadata = { author: 'The Dummy App Team', locale: 'en_GB', description: 'Site-wide description' }
     end
 
     metadata = Perron::Resource::Metadata.new(
@@ -83,68 +83,68 @@ def setup
       collection: @pages_collection
     ).data
 
-    assert_equal "The Dummy App Team", metadata.author
-    assert_equal "en_GB", metadata.locale
-    assert_equal "en_GB", metadata.og_locale
+    assert_equal 'The Dummy App Team', metadata.author
+    assert_equal 'en_GB', metadata.locale
+    assert_equal 'en_GB', metadata.og_locale
 
-    assert_equal "This is the about page.", metadata.description
-    assert_equal "This is the about page.", metadata.og_description
+    assert_equal 'This is the about page.', metadata.description
+    assert_equal 'This is the about page.', metadata.og_description
   end
 
-  test "metadata precedence is frontmatter > collection > site" do
-    resource = Content::Post.new("test/dummy/app/content/posts/2023-06-15-another-post.md")
+  test 'metadata precedence is frontmatter > collection > site' do
+    resource = Content::Post.new('test/dummy/app/content/posts/2023-06-15-another-post.md')
     frontmatter = Perron::Resource::Separator.new(resource.raw_content).frontmatter
 
     Perron.configure do |config|
-      config.metadata.author = "Site Author"
+      config.metadata.author = 'Site Author'
     end
 
-    collection = Perron::Site.collection("posts")
+    collection = Perron::Site.collection('posts')
     metadata = Perron::Resource::Metadata.new(resource: resource, frontmatter: frontmatter, collection: collection).data
 
-    assert_equal "Kendall", metadata.author, "Frontmatter author should take highest precedence"
+    assert_equal 'Kendall', metadata.author, 'Frontmatter author should take highest precedence'
   end
 
-  test "removes nil values from final data after processing" do
+  test 'removes nil values from final data after processing' do
     metadata = Perron::Resource::Metadata.new(
       resource: @about_page,
       frontmatter: @about_page_frontmatter,
       collection: @pages_collection
     ).data
 
-    assert_not metadata.key?(:image), "key :image should be removed"
-    assert_not metadata.key?(:og_image), "key :og_image should be removed"
-    assert_not metadata.key?(:twitter_image), "key :twitter_image should be removed"
-    assert_not metadata.key?(:author), "key :author should be removed"
+    assert_not metadata.key?(:image), 'key :image should be removed'
+    assert_not metadata.key?(:og_image), 'key :og_image should be removed'
+    assert_not metadata.key?(:twitter_image), 'key :twitter_image should be removed'
+    assert_not metadata.key?(:author), 'key :author should be removed'
   end
 
-  test "generates canonical url for root" do
+  test 'generates canonical url for root' do
     metadata = Perron::Resource::Metadata.new(
       resource: @root_page,
       frontmatter: @root_page_frontmatter,
       collection: @pages_collection
     ).data
 
-    assert_equal "http://localhost:3000/", metadata.og_url
+    assert_equal 'http://localhost:3000/', metadata.og_url
   end
 
-  test "generates canonical url with trailing slash when configured" do
+  test 'generates canonical url with trailing slash when configured' do
     metadata = Perron::Resource::Metadata.new(
       resource: @about_page,
       frontmatter: @about_page_frontmatter,
       collection: @pages_collection
     ).data
 
-    assert_equal "http://localhost:3000/about/", metadata.og_url
+    assert_equal 'http://localhost:3000/about/', metadata.og_url
   end
 
-  test "title falls back to site name if not present anywhere" do
+  test 'title falls back to site name if not present anywhere' do
     metadata = Perron::Resource::Metadata.new(
       resource: @about_page,
       frontmatter: {},
       collection: @pages_collection
     ).data
 
-    assert_equal "Dummy App", metadata.title, "Title should fall back to the configured site_name"
+    assert_equal 'Dummy App', metadata.title, 'Title should fall back to the configured site_name'
   end
 end