An image forming system includes an image forming device which forms an image based on image data, and an image processing device such as a personal computer, and the image forming system is capable of restricting image output of the image forming device. In the image forming system, data information of the output image data or working environment of the image forming device is judged, so as to allow or disallow image output based on the working environment so judged. This judges whether or not devices such as digital complex device or scanner device in the image forming system are used properly, thus providing an image processing system which can be used efficiently.