Question about iTunes album art?

I have several albums with different artwork on each song, for various reasons. Some are compilations of different artists and some I just want specific pictures with certain songs, like singles and what not. So when I look at my library, it shows the album artwork right? So it has to pick one to display as the overall artwork for the whole album. I think it just chooses the one from the first song. I want to know if there's any way to change how it chooses that or pick a specific picture to be the artwork it displays without changing the artwork on the first song. Thanks if you can help :)