An image processing system includes a first image processor that reads out a first image written in a main memory to apply a first process to the first image and write in the main memory as a second image, a second image processor that reads out a second image written in the main memory to apply a second process to the second image and write in the main memory as a second image, and an address snooping apparatus that snoops an address of the image written in the main memory to start the first process when the address is indicated to a previously set first value and start the second process when the address is indicated to a previously set second value, effectively enabling synchronization between a process by a CPU or a special purpose processor and a data delivery/receipt process between pipeline stages.