I looked on one of my old posts (#90810). The thumbnail is still in the gallery, but when I click on it I get a list of tags where the image should be.
This doesn't look like a deletion. Refreshing doesn't help. I've looked in on the imahe a day later and encounter the same problem. Has anyone else found this?

Same on post 176849

Tag it 'broken image', this is related to the similar issue where some images falsely report as "blocked from your region" IIRC.

Yeah, I've seen it happen on a few images, and clicking on "Original Image" brings up the Access Restricted page too

How strange. I tried clicking on "original image" and the image appeared. Maybe it is only the downsized image that is messed up?

Has happened before; I still recommend tagging it 'broken_image' so a moderator can track it down and fix it.