That's interesting, Phil, because althouh I've had no previous problems I opened Tim Watson's latest two postings and a few of the pictures had the IMG description and no photo. However, following some earlier advice (sorry I can't remember who) I hovered over the "IMG" and hit Fn and F5 together and the relevant picture appeared.
There's something funny going on, though, as I've historically had none of these problems. I'm using Google Chrome.
Brian
Edit - I've just gone back to Tim's posts to finish reading them and found that early entries, even as early as the first page of his thread are showing the same characteristic. At this stage I don't know whether this is strictly limited to Tim's postings or if I'll find the problem to be more general. I'll report if it happens again. Not insurmountable, though, using the Fn/F5.