Custom social preview uploads create 404 URLs across repositories

[PedroPorto021]

🏷️ Discussion Type

Bug

Body

Problem

Custom social preview images uploaded through repository settings are not available after GitHub accepts the upload.

The preview area remains blank, and each generated repository-images.githubusercontent.com URL returns:

HTTP 404
WebContentNotFound

Affected public repositories

• https://github.com/PedroPorto021/SistemaGestao
• https://github.com/PedroPorto021/Projeto01

Steps to reproduce

1. Open a public repository.
2. Go to Settings.
3. Find Social preview.
4. Upload a valid JPG image.
5. Wait for GitHub to finish the upload.
6. Open the generated social image URL.

Tests performed

• Valid JPG and PNG files under 1 MB.
• Dimensions of 640x320 and 1280x640 pixels.
• Tests performed on different days.
• Reprocessed JPG file without transparency.
• The same 640x320 JPG tested on two different public repositories.
• Every upload generated a different image URL, but every URL returned HTTP 404.

Example URLs returning 404:

• https://repository-images.githubusercontent.com/1338988136/bb4aa1f5-66e0-4687-a76d-20805f64c442
• https://repository-images.githubusercontent.com/1335508376/ef0d5930-2afa-4514-9f78-9a0fb1ae4db1

Expected result

The uploaded custom image should appear in repository settings and be available through the generated social preview URL.

Actual result

GitHub updates the repository metadata with a new image URL, but that URL returns HTTP 404 WebContentNotFound.

When the custom image is removed, GitHub's default Open Graph preview works correctly and returns HTTP 200.

Is this a known issue with social preview image storage or delivery?

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[Vendetaaaa]

Issue:

When a custom social preview image is uploaded under Settings → General → Social preview, GitHub successfully registers the metadata and updates the repository's og:image meta tag to point to a newly minted repository-images.githubusercontent.com/[repo-id]/[asset-uuid] URL. However, the backend upload/commit step fails to persist the actual file asset into the underlying storage container (evidenced by the x-ms-error-code: WebContentNotFound response header).

Workaround

Until GitHub deploys a fix to their asset upload and confirmation handler:

1. Navigate to Settings → General → Social preview.
2. Clear the broken custom image.
3. Avoid re-uploading custom images for now.

[PedroPorto021]

Thank you for confirming the issue and explaining the storage behavior. I removed the custom images from both repositories, and the default Open Graph previews are working correctly. I will keep this workaround and monitor the discussion for updates.