Unfurled Image and Avatars for remote users should be stored, not cached

[lindner]

Is your feature request related to a problem? Please describe.

If furled content changes the image preview can disappear or change. Leading to a display that is not acceptable.

Avatar changes and account deletions can also leave poor broken image results.

Describe the solution you'd like

Unfurled images should be stored and not cached.

For comments that users leave on remote platforms (twitter/mastodon) the fetched image should be stored locally and not cached..

[mapkyca]

Cache = Store, really. But, perhaps some tweaking to the logic would work.

The image proxy obeys cache headers, and I think also obeys http statuses. Perhaps an approach would be to check for non 200 codes on images and not replace the old image if the new one couldn't be retrieved.... I thought it did that already, but I wrote that code so long ago!