In the related art, games are known in which an image of a part of a user's body such as a head is captured by a video camera, a predetermined area (e.g., an area including an image of an eye, a mouth, a hand, or the like) is extracted from the image, and the area is replaced with another image so as to be displayed on a display (for example, see patent document No. 1). A user interface is also known that receives, as an instruction for operating an application, the movement of a mouth or a hand captured by a video camera.