1. A method comprising: accessing a first captured image that includes (1) a first display produced at a first point in time by a set of instructions executed by a computing device, and (2) a user interacting with the first display and not part of the first display; accessing a second captured image that includes (1) a second display produced at a second point in time by the set of instructions executed by the computing device, and (2) the user interacting with the second display and not part of the second display; comparing the first captured image and the second captured image; determining motion of the user, based on a result of the comparing of the first captured image and the second captured image; and relating the determined motion of the user to a portion of one or more of the first and second captured images.