The expression of satisfaction at the acts of torture one is inflicting on helpless, trussed, naked victims is only part of the story. There is the primal satisfaction of being photographed, to which one is more inclined to respond not with a stiff, direct gaze (as in former times) but with glee. The events are in part designed to be photographed. The grin is a grin for the camera. There would be something missing if, after stacking the naked men, you couldn't take a picture of them.
Susan Sontag