Image data captured by digital cameras are shared among the digital cameras. Image data captured by digital cameras constituting members of an image-sharing group are shared, by way of a network, within the image-sharing group. Every time captured image data are output, the digital camera generates for each of the members distribution information, including a storage source directory, a distribution destination address, and a storage destination directory, all pertaining to the image data, by reference to a group list where member information is registered for each of the members, including a distribution destination address and a storage destination directory, to thus generate a distribution list having respective pieces of distribution information registered therein. Further, the digital camera sequentially reads distribution information from the distribution list and distributes the image data to respective other digital cameras, which constitute the members, on the basis of the read distribution information.