When iTunes flunks on your Album Art, simply go to Amazon and find the listing for the CD and copy the large jpg file to your computer and apply it to the CD with the missing art.
Good tip. I've had a question regarding this that I've yet to be able to find an answer for, so I'll try posting it here: On many of my CD's that don't show up any artwork (I've gathered as much as I could automatically from Apple, and the rest scavenging from Amazon or elsewhere on the net) there is a message in the artwork window where you'd normally drag your artwork to reading "Artwork not Modifiable". I read on one chat site that it was because the file was imported as a WAV file, which is indeed the case with my files. BUT there are many WAV files in my library where I DO have artwork for the CD which was automatically acquired through Apple. If I Apple can tag the WAV file for artwork, why can't I?!
Marco