Images size regression after LTSC2019?

[slonopotamus]

In previous years, there were multiple optimizations to Windows container image sizes.

• Reducing the size of Windows Server Container Images – Part 1
• Reducing the size of Windows Server Container Images – Part 2
• Making Windows Server Core Containers 40% Smaller
• We made Windows Server Core container images >40% smaller
• A smaller Windows Server Core Container with better Application Compatibility

However, if we look at the full picture, we will find out that lots of savings are lost after LTSC2019.

Image	Unpacked size	ID
mcr.microsoft.com/windows/servercore:ltsc2016	10.3GB	2d2526d785fa
mcr.microsoft.com/windows/servercore:ltsc2019	4.84GB	a618c5dca893
mcr.microsoft.com/windows/servercore:ltsc2022	5.16GB	7f1b8b9185ba
mcr.microsoft.com/windows/servercore:ltsc2025	6.86GB	839fb663b94d

Another interesting case is mcr.microsoft.com/windows vs mcr.microsoft.com/windows/server. While this page claims that mcr.microsoft.com/windows/server is "slightly smaller than the Windows image", this is very far from being true:

Image	Unpacked size	ID
mcr.microsoft.com/windows:ltsc2019	9.62GB	3d607df24767
mcr.microsoft.com/windows/server:ltsc2022	10.7GB	cf92e62dbd14
mcr.microsoft.com/windows/server:ltsc2025	15.9GB (ouch!)	2fcb8c1b2d80

And finally, nanoserver:

Image	Unpacked size	ID
mcr.microsoft.com/windows/nanoserver:ltsc2019	255MB	1090b09192bc
mcr.microsoft.com/windows/nanoserver:ltsc2022	293MB	33403772621b
mcr.microsoft.com/windows/nanoserver:ltsc2025	501MB (ouch again!)	571e1fba94e7

So, my question is: what has happened to images after LTSC2019 and can't we return back to the smaller sizes?

P.S. Unpacked size and ID were determined by running docker image ls

[github-actions]

Thank you for creating an Issue. Please note that GitHub is not an official channel for Microsoft support requests. To create an official support request, please open a ticket here. Microsoft and the GitHub Community strive to provide a best effort in answering questions and supporting Issues on GitHub.

[pBogey]

update from me: make the damn images smaller!

[microsoft-github-policy-service]

This issue has been open for 30 days with no updates.
no assignees, please provide an update or close this issue.

[microsoft-github-policy-service]

This issue has been open for 30 days with no updates.
no assignees, please provide an update or close this issue.

[akarshm]

Thanks for reaching out, @slonopotamus! We’ve rebaselined the Windows Server Container images for WS2016, WS2019, and WS2022 as part of the October 2025 security update. The compressed size for WS2022 Server Core is now 1.34 GB, down from 1.58 GB for WS2019. Keep in mind these sizes will grow monthly as we add new delta layers to keep the images patched. To stay current, I recommend pulling the latest image from the Microsoft Artifact Registry (here). Let us know if you have any other questions!