I can add a bit here:
When I've just posted a reply to something I don't see my picture on that post only, there's a little red X there instead; but my picture's still there on other earlier posts in the same thread. When I go to any other page then reload the page where I just posted, my picture has appeared where it should be.
So the only way to test this would be to reply to something then immediately look and see if your picture is present after you hit "submit" but before doing anything else.
Lanefan
EDIT: and it's intermittent - my picture appeared on this reply just fine but did not appear on a reply I made a few minutes ago in the Battle of the Bards news thread.
Second EDIT: and my picture did not appear after submitting the first edit...I'd edited the BotB reply as well before I noticed the missing picture, so I wonder if the problem only arises when one edits a post?
Third EDIT: this time instead of a little red X I see a little blue circle with a line through it.