I found a cd cover art site last night with an inventory of high quality scans, which I used to replace a few dozen of the covers that I did not feel iTunes had done a good job on.
If you look on a cover that has the color red in it, like, Duran Duran’s Red Carpet Massacre, or U2’s How to Dismantle An Atomic Bomb, you’ll notice that there are tons of compression artifacts (“squiggles”). These squiggles are always most noticeable with the color red which is why I mentioned it, but they’re visible everywhere if you look closely. (And sometimes iTunes is just plain lazy, and you’ll see the staples on the side of the cover booklet, or you’ll see a fraction of an inch beyond the edge of the cover.)
The cover art provided by www.albumartexchange.com is much higher quality. Covers scanned by quality fanatics. The kind of people who notice a JPG squiggle and demand better. All in 600×600 or greater, and saved with hardly any compression.
I’ve just sent the owner of the site a message telling him to scuttle his plans to open a similar site for DVD covers, reminding him that while CD covers seem to be accepted now as something people need to make their portable players look nice, DVD cover art is an entirely different matter. A few years ago, a DVD cover art site was sued out of existence, and that same level of enforcement will surely be brought to bear on him. I used lots of CAPS to urge him not to launch it.