Expanded images are too small due to only showing thumbnails

[Nothing4You]

Requirements

• This is a bug report, and if not, please post to https://lemmy.ml/c/lemmy_support instead.
• Please check to see if this issue already exists.
• It's a single bug. Do not report multiple bugs in one issue.
• It's a frontend issue, not a backend issue; Otherwise please create an issue on the backend repo instead.

Summary

Lemmy-UI uses the thumbnail URL when showing expanded images.
As thumbnails are now limited in size this is no longer suitable for full size images for expansion.

Steps to Reproduce

1. Create post to an image URL with a resolution larger than 256x256
2. Expand image of post

Technical Details

LemmyNet/lemmy#5107 restricts the resolution of generated thumbnails.

Example:
https://lemmy.ml/post/22206928

https://sh.itjust.works/post/27691217

Lemmy Instance Version

0.19.6-beta.15

Lemmy Instance URL

https://lemmy.ml/

[dessalines]

Its a backend issue, so I'll close this one in favor of it: #2796