iTunes on a network drive finally got to be unworkable with version 10 and I was forced to buy a new system with a big enough hard drive to handle a 1T library. I imported my music with the “find missing artwork” setting turned off and when I was done there were a couple hundred albums without art. Most of these were either things from before I started making sure I had art locally or were from artists where I had imported a large batch at the same time (and probably got sloppy.) All of the missing albums were commercial releases and by pretty popular artists so that iTunes was able to find art for them – ortherwise I would have noticed and fixed the absence long ago.
So – in no particular order – here is the artwork that is now stored in the MP3s in my library.