My new profile picture isn't showing on other people's profiles after changing the old one.

My miniature jpg (the "_mini.jpg") profile picture won't show on other people's profiles after I changed it. In fact, the new picture is still pointing to the web address of the old one at Amazon S3. Its upload size is only 15KB
The "_normal.jpg" picture is working fine though.

I tried deleting it and uploading the new one several times with the same name and dimensions as the old one - and this quick fix partially worked, now it's showing on some profiles but not on others. Looks like it went from a bug status to a glitch :)