In case of a "N-up" function, a correcting unit executes a correcting process operation with respect to an image read by an image input unit, a editing unit executes a magnification changing process operation, and thereafter, "N" sheets of images are placed side by side to form a single synthesized image at a time when the processed image is stored into a storage unit 15. When transmitting the synthesized image, an attribute of the image set from a U/I is added to the synthesized image and the control unit transmits the resulting image to an external apparatus. As a result, a reception side can execute an optimum processing operation with respect to the synthesized image with reference to the attribute added to the image. As a consequence, even in a "network copy", the "N-up" function can be realized in a high image quality similar to that of a "direct copy".