Image display system, image display system control method, image distribution system, and head-mounted display

Provided is a game system 100 to which an image display system is applied, comprising: a head-mounted display 300, further comprising a camera which captures a real-world image, and a screen which displays a fusion of virtual-world video information with real-world video information which has been captured by the camera; a motion sensor 400 which detects, as action information, a movement of the body of a wearer who wears the head-mounted display 300; and a marker 200 which is for detecting position information of the wearer. The virtual-world video information is controlled on the basis of the action information and the position information. It is thus possible to control video information which is displayed upon a head-mounted display according to the position and movement of a wearer. The present invention additionally provides an image display system control method, image distribution system, and head-mounted display.