They don't have to be legal, the tag info just has to match whatever sort of database or whatever that Apple has.
BTW I've found that iT7 finds more album art than what they they have in the music store. I thought it was limited to what they had, but it finds art for albums that they don't sell. Maybe I'm the only one who didn't realize this.![]()
If iTunes music store does not have it they don't get the art. Period. I've tried it. It will not retrieve artwork it doesn't have. Check again.