In an image storing method for storing image signals, which represent images, in a storage device, a plurality of image signals, which represent a single image and have been subjected to different processes with respect to at least both of resolution altering processing and image processing, are stored in the storage device. In a network comprising a plurality of image output devices having different levels of image displaying quality according to purposes for which the displayed images are used, the image signals having been read from the storage device are capable of being quickly transferred or outputted according to purposes for which the displayed images are used.