New src_matched value filter request

[rahu1]

Hi,

I am uploading media to Amazon S3 and serving media URLs directly from S3. All media URLs are successfully replaced and served from S3 without issues.

However, when I enable object versioning in S3, WordPress fails to generate srcset. Specifically, the URL becomes something like:

​https://.../any/uploads/2026/01/8728723/a.jpg

This happens because wp_calculate_image_srcset() receives the S3 URL as $image_src, since the URL is already replaced via a the_content filter. Due to this, the internal src_matched check fails, and the function simply returns false.

As a result, no srcset is generated.

I need a filter or hook inside wp_calculate_image_srcset() to detect whether the provided image URL is an S3 URL. If it is, I need a way to force the src_matched check to return true.

I have already tested this by modifying wp_calculate_image_srcset() directly, and it successfully generates image sizes using the S3 URLs. However, modifying core is not a viable solution, so I am looking for a proper filter-based approach.

Any guidance or suggestions would be appreciated.

Thank you.

[heetwp]

I’d like to work on this and will submit a patch soon.