WebP Images resolution not working in Gutenberg on wordpress.com | Modern Image Format

[tehjaymo]

Bug Description

I recently moved hosts returning to wordpress.com.
I've been using the Modern Image Formats plugin since release without issue.

However, since the site move whenever I upload a new image in the editor I get an error: "This image has an empty alt attribute; its file name is G0061259-1024x768.webp"

which is weird because the plugin re-names the file with -jpg- The block should be looking for G0061259-jpg-1024x768.webp or whatever image resolution was produced. The error occurs on all file resolution sizes except 'original' which displays correctly in the editor.

All images however display correctly on the front end.

Steps to reproduce

1. Go to wordpress.com hosted blog
2. Install the Modern Image Formats plugin
3. Upload an image in the editor
4. See error

Screenshots

Additional Context

WordPress 6.6.1
PHP 8.1
Gutenberg 19.0.0

Whatever the wordpress.com Business hosting plan standard Nginx plan setting are.

Existing files and pages pre move have no issues. Only new uploads.

Selecting 'Outputi JPEG images in addition to the modern format' solves the issue in the editor, webp images display on the front end.
But this isn't too sustainable long term imo.

[westonruter]

Aside: On WordPress.com there is an Image CDN which should automatically serve WebP for uploaded images.

[adamsilverstein]

Thanks for the bug report @tehjaymo... As @westonruter points out above, you may not need this plugin with wp.com already offering an image CDN with WebP support built in (but not AVIF afaik).

Still, I'm curious if I can reproduce, can you confirm what type of plan you are on?

Also, can you check Tools->Site Health->Info->Media and report back here what Editor/filetype support is listed?

[tehjaymo]

Huh, thats weird. I've testes with the plugin turned of but CD turned on and it only seems to server resized jpgs. Anywhoos here's the info from my site health

Active editor	Photon_Subsizes_WP_Image_Editor_GD
ImageMagick version number	Not available
ImageMagick version string	Not available
Imagick version	Not available
File uploads	Enabled
Max size of post data allowed	2047M
Max size of an uploaded file	2047M
Max effective file size	2 GB
Max number of files allowed	20
GD version	bundled (2.1.0 compatible)
GD supported file formats	GIF, JPEG, PNG, WebP, BMP, AVIF
Ghostscript version	Not available