This was mentioned before, but I hadn't seen it. However, now I have. I put a couple of embedded pictures into a post, all was fine. Then I went back and edited the post (not touching the pictures or links), and when I looked at the post, the pictures were just blank placeholders! I edited it again and deleted the blank placeholders and embedded the pictures again, and they stayed.
This is the post, though the pictures are still intact: https://ogrforum.com/...7#154730473567999847
Is there some operation that might cause them to disappear like that?