I prefer to use MediaMonkey on my PC to manage my album art. As a one-time process, I organized my music into <artist>/<album> folders and used a script I found on their user forums to extract my MP3's embedded album art, resize to 300x300 and 150x150, add them to the album directories. Then I used rsync to copy over the music collection to my N800. Once I created a symbolic link from ~/.canola/covers to my music collection, it displayed everything just fine.