[SirDrexl]

If you don't mind starting a new game, copy the stadium images to the data\ballparks folder. If they are named properly they will work from then on. The images in the all-in-one pack or the pack from The Show are already named correctly (the same images are in each).

Oh, it's just the major league stadiums though. Maybe someone will do some of the minor leagues at some point. They're fictional, but at least they'd be nice images to use.