An image processing system comprises: an image processing device capable of displaying a screen; and a terminal device that communicates with the image processing device and operates the image processing device via a remote control. The image processing device sends the screen to the terminal device, thereby enabling the terminal device to display the screen, and determines an application to run on the terminal device based on the screen and sends application running information specified by the determination result or cooperative application information corresponding to the application running information, to the terminal device. The terminal device displays the screen received from the image processing device, and runs the application based on the application running information or the cooperative application information received from the image processing device.