A receiver sets a storage capacity to be assigned for each connected digital camera based on the number of connected digital cameras, and allocates these storage capacities in a buffer. Also, the receiver sends a request for a through image for each frame to each of the connected digital cameras, receives through images transmitted in response to the requests, and stores the through images in areas of the buffer assigned for each of the digital cameras. Furthermore, after receiving the through image for one frame from each digital camera, the receiver performs image processing on each through image and causes these images to be displayed in a list form on one screen of the display section.