I recently manually added (by that I mean not bought off the iTunes Store) 2 series of a TV show. I found some artwork to replace the "opening minute frame" that's automatically shown, but I've had a bit of a problem. While the first series was fine, the first and last episodes in the second series refuse to "accept" the artwork. I go to Get Info -> Artwork, Add it, click OK, but there's no change - and when I go back into Get Info, there's nothing there, as if I never added the artwork! Is there any way of fixing this? Thanks in advance!