If ya want free then ya better grab a 6 pack of rockstars and prepare you browser for a serious Google overload. Especially if ya got a shiit load of music. Trust me, I've been there. And the obscure albums... ouch. Finding good cover art for those and at a good size (rez) is, shall we say close to miraculous.
I use itunes, but don't have an account, cause it cost money, and don't you have to pay for the album art you download from them?
I have most of the cd's that are in my library, just the art isn't on the computer. I have done the google thing in the past, and it sucks lol. I thought by now there would be some cool way of getting all.
Alright, I guess I have a boring weekend coming up lol.
Can't you just tag the albums you want, and then get new info/including album art? I know several players will do this. I also think there is an app that will do this for you, it resolves around the CDDB or gracenote.