An image display system allowing a plurality of users to enjoy viewing programs is provided. The image display system includes a plurality of television sets connected to the Internet, and an IP telephone management server. The IP telephone management server has a friend list as data including information about television sets allowing communications via IP telephones in a memory. The friend listincludes identification numbers of the television sets connected to the IP telephone management server, IP addresses of the television sets and numbers of channels selected in the television sets. Information (e.g., the number of the selected channel and the user of the television set) representing images displayed on each television is transmitted as a viewing history to the IP telephone management server to prepare or update data items in the friend list.