An image display system includes a display capable of performing mixed display of 2D and 3D images and a host computer for supplying image data to the display. An image source generation unit of the host computer generates image data to be displayed on the display. A 3D display position/area information generation unit generates area information indicating the 3D image area of the image data. A display mode setting unit generates display mode information on the basis of the setting indicating whether to perform mixed display. In the display, when a display mode detection unit detects the execution of mixed display from the display mode information, a 3D display position/area control unit ensures a 3D display area in accordance with the area information, and an image display unit performs mixed display.