Trouble changing the photo slide show in background

Hello I have had a few different wordpress themes over the years, and I always have trouble changing the background image. I just upgraded to Rockstar Pro. Love this theme!!! Problem is I want to change the background photos (I am referring to the photos of the guys with the guitars in the images that take up the whole screen) but am stuck I am NOT referring to the background image. I am good with that. Please help Curt