Before iTunes 9, there was a "Display album artwork" checkbox. By disabling then reenabling it you could rebuild the album artwork database on the iPod (when it gets corrupt by programs like Songbird).
However, I cannot seem to find that checkbox in iTunes 9. It is gone forever, or just hidden?
How can I rebuild the album artwork database on an iPod when it gets corrupt?
The album artwork is embedded into the files, so I just need to rebuild the artwork database in {iPod}\iPod_Control\Artwork
so the iPod displays them correctly. Retransferring all the media again to the iPod would be my last option.