A game system 100 to which an image display system is applied contains a head-mounted display 300 having a camera for capturing a real world and a display for displaying video information obtained by integrating real-world video information captured by the capturing part with virtual-world video information, a motion sensor 400 for detecting movement of a body of a wearer wearing the head-mounted display 300 as movement information and a marker 200 used for detecting position information of the wearer. The game system 100 controls the virtual-world video information based on the movement information and the position information. According to this configuration, it is possible to control the video information displayed on the head-mounted display according to the position and the movement of the wearer. Further, the present invention provides a method for controlling the image display system, an image distribution system and a head-mounted display.