1. A non-transitory computer readable storage medium storing game program instructions, the game program instructions being configured to: acquire a first user image captured by a camera before starting a game processing; generate user feature data indicating a feature of a user based on the first user image; store the user feature data; acquire a second user image captured by the camera after starting the game processing; determine whether or not the second user image includes the feature of the user by comparing the second user image with the stored user feature data; and execute the game processing based on the second user image when the second user image includes the feature of the user.