A communication terminal (3d) requests a communication
management system (5) that relays image data transmitted from other communication terminal (3a, 7, 9) to control resolution of the transmitted image data. The communication terminal (3d) includes required resolution management means (3004d, 302, 303, 304) for managing, for each
image type information indicating a type of image data, sizes of a plurality of display areas of display means (4d), each display area being a divided area divided from an entire area displayable by the display means (4d), in association with required resolutions of image data to be displayed in the corresponding display areas. The communication terminal (3d) further includes receiving means (31d, 301, 311) for receiving, from the communication
management system (5), specific
image type information indicating a type of specific image data transmitted from the other communication terminal (3a, 7, 9). The communication terminal (3d) further includes transmitting means (31d, 301, 311) for transmitting, to the communication
management system (5), specific required resolution, which is a resolution stored by the required resolution management means (3004d, 302, 303, 304), for the specific
image type information, in association with the size of one of the display areas in which the specific image data is to be displayed.