Responsive Sizes Ignored on Offloaded Media

I’m using the S3-Uploads plugin to offload media files to S3 storage. The plugin correctly copies the media and sets a media URL override in the image gallery, including the generated sizes of the image.

Unfortunately, when setting one of these images in a Cwicly image block, it doesn’t map the srcset for the responsive sizes. Instead, it just links to the full size image as if it were an external resource.

Here’s an example image when set from a standard WordPress image block (includes responsive sizes):
<img data-dominant-color="627132" data-has-transparency="false" style="--dominant-color: #627132;" decoding="async" width="1024" height="576" src="" alt="Woman and Girl Walking at Banaue Rice Terraces" class="not-transparent wp-image-93" srcset=" 1024w, 300w, 150w, 768w, 1536w, 1600w" sizes="(max-width: 1024px) 100vw, 1024px" loading="lazy" fetchpriority="low">

Here’s the same image when loaded in a Cwicly image block (responsive sizes missing):
<img decoding="async" class="image-background cc-img" src="" width="1600" height="900" alt="Woman and Girl Walking at Banaue Rice Terraces" loading="lazy" fetchpriority="low">

I’m submitting this as a bug because the links to responsive sizes are clearly available and linked to the media item, but Cwicly is ignoring them, presumably simply because of the domain mismatch.

This is a big issue for the efficient delivery of a site.

Facing the same issue, I was also planning to open the report. I have been shifting the client’s media library to Amazon S3 for the purpose of redundancy. I have set up multiple servers hosting the same site, all pointing to the same media library via S3 to ensure redundancy.

Hello @avunu and @dranzer,

Thank you for the report.

I’m sorry to hear you’re having trouble with this.
It does sound unusual as we are using the usual wp_get_attachment_image_srcset function to get the image srcset.

I’m not familiar with this plugin.
Could there be some type of ID modification?
Were the Gutenberg and Cwicly image blocks modified at the same time?
Can you try adding a new Cwicly image block and see if it the srcset and sizes attributes are added?

Thanks in advance.