Interesting thing that Windows Media Player 11 does to the artwork on albums you possess is to place them in a cache directory under %USERPROFILE%\Local Settings\Application Data\Microsoft\Media Player\Art Cache\LocalMLS. Each one is names after a guid, which is probably generated for each track in the collection.
I’m just wondering how difficult it would have been to use a hash of the image data as it’s file name, and storing the hash in the media library instead of the pointer to the guid. This way when you have duplicate images (typically 10 per album), they are not replicated into the cache of images.
The other complaint is that I’ve got a bunch of black album art images. It’s completely odd, as they seem to be completely ok inside in the file – other tools have no difficulty in examining them, and show correct icons. Maybe I should feed this back to them – after all it’s a beta of media player 11.