It’s behind you!
I remember when everyone at college had a cardboard cutout of some celebrity in their dorm room, that they’d stolen from the local multiplex or mall. We’d all laugh and take photos of ourselves with it. These guys look pretty excited to be taking their picture with a picture.
I can’t imagine how excited they’ll be when they turn around and realize that they could have been taking their picture with the real life guy from the photo, who’s sitting behind them and taking their picture. It’s all very meta!