iPhone Life magazine

Search for missing album cover art

Issue: 

To search for missing artwork, open iTunes on your PC or Mac, select Advanced >Get Album Artwork. As long as you have an iTunes account and an active connection to the Internet, iTunes will attempt to retrieve artwork for any albums and videos in your library that is in the iTunes Store's catalog.

http://www.iphonelife.com/issues/2010Summer/TipsForIPhone3GS