This is constantly an issue for me and has been for a long time. It never seems to work right. Example -- I'll pull in a bunch of TV shows from DVDs that I have ripped from my personal collection. It automatically grabs a random screenshot from the movie to use as the "Cover Art." So, I go to Amazon.com to grab a copy of the DVD box art, or something similar to use instead. I select all the shows in iTunes, drag the image to the bottom left -- I see iTunes process a bunch of stuff, I see the artwork show up for a second, and I hear my external hard drive working away. Then, it's gone. Or, if I try updating artwork for just one title, by clicking -I and dragging it into the info for the one item; it doesn't work there either. You'll also notice that it shows nothing in there before I drag something in, even though the display shows something old. Why does it do this?!? It's not a permissions issue on the drive or anything, I checked. Sometimes I can get it to cooperate after trying over and over and over, but it's random...no rhyme or reason to it, and I'm not sure why it eventually cooperates. In the case of the one I'm trying to do now, nothing has worked. I posted a video of what happens so you can see that I'm not crazy -- nothing I do sticks. Sorry for the poor quality but, you can at least see what's happening.