Display system, network interactive display device, terminal, and control program

A technique for presenting display screens of a plurality terminals (1a - 1d) connected to a network (3) on a multi-window screen of a display screen of a display device (2). A communication unit (28) receives image data captured and then sent by each terminal having a screen capture function. A display control unit (22) controls an image synthesizer (42) to synthesize the captured image data into single screen multi-window format data. A multi-window screen is thus presented.