An image input and output system is provided in which a common operation screen for a plurality of image output devices having different attributes is displayed. Based on attribute information of each of printers, the server generates a signal for generating an operation screen, and transmits the signal to the scanner. At the scanner, image data is inputted, and a common operation screen, which is generated based on the signal for generating the operation screen, is displayed on a display panel. When information designating the printer and information relating to an output format of an image is inputted from the display panel, the inputted information and the image data are transmitted to the server. The server transmits, to a designated printer, the image data and the information relating to the output format of the image, which are transmitted from the scanner, and images are outputted.