I wont go into debate about the thumbnail stuff, lol you couldn't pay me.

But simply put, edit and delete out that particular image from your gallery.  Then re-post it and it will show up new in the top of the list.  If you decide to leave it where it is, that's all good too.  Those that favorited your spot are wise enough to realize there's a problem and check back later.......

Or one would assume.