A transfer unit and an image output control unit are provided in order to check and prevent any alteration or forgery of image file data in a memory card. The transfer unit transfers a digital signature of the image file data stored in the memory card, a secret key used for the digital signature or a public key paired to the secret key, together with the image file data and a property file, to an image control apparatus. The image output control unit controls an image output in accordance with the information transferred by the transfer unit.