Well doesn't take long as you do it as you go along. Sgt Peppers needs a cover, just go to a site like discogs.com, copy a nice version of the cover, plop it into MediaMonkey, and done.
The thing is that Media Player 11 was different. It would show the embedded album cover at it's 100% size, so even if you had a huge one, it didn't, at the very least, shrink it to the size of the area it's in it just filled up the whole area. Speaking of the Now Playing area here of course.