Still something not right.  Image uploaded for https://musicbrainz.org/edit/49511644 still not showing up.

Ah - you are right. Hardware issue has been fixed.

https://archive.org/derive-wait.php is where it reported that.

So it does look like a new or repeated issue.

Are you sure it was a hardware issue? Because out of 40+ CA additions from me today, only those 3 are broken and only those had an existing CA which I moved to position 2 when adding my CA. Could you try to reproduce it?

Edit: 2 out of 3 work as of this moment.

Some sort of hardware issue this time - awaiting a new harddrive I believe.

I believe I encountered this problem today. For 3 of my edits, the CAA page displays "Page not found" when clicking on 250 and 500px thumbnails, mb shows "We are unable to display history for this cover art. For a current listing of cover art, please see the release's cover art page." text on the edit.

However I know why it happened for these particular releases and it should be easily reproducible. All of these releases already had a front cover image attached to them. I went to the Cover Art tab, clicked on the "Add Cover Art" button, then pressed the left arrow on the "New Image Goes Here" tile so the CA I am adding will be on position 1. Then I clicked "select images..." buton, found the image in my pc, selected "Front" cover type and then entered the edit (the existing image also had the "Front" type set). After this, the thumbnails never appeared. My other cover edits which I added later are already displayed on my edits and both 250 and 500px versions work correctly. I have not tried if the edits would pass if you select the image first and then use the left arrow to move it to position 1.

I suspect that we need a batch script run to identify where the smaller versions of cover art have not been created and to create them again automatically.

What's the suggested workaround, remove it and then add again? I have https://musicbrainz.org/edit/45699193 , now over a month old. Is there a time period after which there's no point waiting for it to sort itself out?

I have several (uploaded on the 29th) that are still stuck as of this writing:
https://musicbrainz.org/release/32e4f2a8-f196-4e9c-b53d-96cee48da2f9/cover-art
https://musicbrainz.org/release/449b6b24-4a59-46ed-b6d3-0c0aad959524/cover-art (the images that aren't showing up were my uploads)

Mine have finally come through: https://beta.musicbrainz.org/release/e5b92085-3788-418e-945b-feeae5add9ed/reorder-cover-art

The last of those was uploaded on 5-27.

On the other hand, I have a new one that's stuck: https://beta.musicbrainz.org/release/feb5ca7e-242e-4053-a981-9d528dc4cd5a/cover-art

Looks to me as if postprocessing of uploaded images in CAA is broken. Sometimes it works, sometimes it doesn't - then thumbnails are not generated (MB can't display images) and the json file describing all cover arts for a release is not updated or created (Picard: CAA JSON error: Error downloading .../index.json).

I have some issues, too:

https://musicbrainz.org/edit/45578668 (+ other images of this release)
https://musicbrainz.org/edit/45582777 (+ other images of this release)
https://musicbrainz.org/edit/45672241
https://musicbrainz.org/edit/45708742 (+ other images of this release)