1. An image processing system comprising: a first image processing device; and a second image processing device for performing an image-related process about an image in cooperation with the first image processing device via a network, wherein the first image processing device is provided with an added function detection portion for detecting a function that is added to the first image processing device, and a function addition informing portion for sending to the second image processing device notice information that indicates that the function is added to the first image processing device, and the second image processing device is provided with a notice information receiving portion for receiving the notice information, and a setting portion for setting the second image processing device so that the image-related process can be performed by using the function indicated in the received notice information.