In an information processing apparatus, when a receiving unit receives data from an external device, a power control unit returns a power state of the apparatus from a power saving state and a transmitting unit transmits a start instruction to a connected image forming apparatus, and when a power supply switch becomes on according to a user's operation, the power control unit returns the power state of the apparatus from the power saving state but the transmitting unit does not transmit the start instruction to the image forming apparatus. Thus, it is possible to achieve both a linkage start and an individual start for an external image processing controller and the image forming apparatus, in an image processing system including the information processing apparatus, the external image processing controller and the image forming apparatus capable of performing an image process in cooperation with others.