When image data is sent and received between cameras via communication, it is possible for the user to ascertain the images that are being communicated. Thumbnail image data for transfer purposes is transmitted from a transmit-side camera to a receive-side camera. Main (full-size) image data is thenceforth transmitted from the transmit-side camera to the receive-side camera. When the main image data is sent and received, display screens on respective ones of the cameras display an image in which a transfer thumbnail image represented by transfer thumbnail image data moves from the display screen on the transmitting side to the display screen on the receiving side.