A control device comprises a first memory, a second memory, and a processor. The first memory is configured to store captured image data and alternative image data. The second memory is configured to store positional data in association with a communication terminal. The processor is configured to: retrieve from the second memory first positional data associated with a first communication terminal and second positional data associated with a second communication terminal; calculate a distance between a first position indicated by the first positional data and a second position indicated by the second positional data; and select image data to be sent to the first communication terminal from among captured image data or alternative image data, on the basis of the calculated distance, to allow the first communication terminal to display an image on the basis of the selected image data.