1. An image processing system, comprising: a first image processing unit, for sequentially receiving a plurality of images; and a second image processing unit, coupled to the first image processing unit, wherein the first image processing unit divides a (K+N) th image into a plurality of regions according to a K th image and a (K+M) th image, K, M and N are integers and N is greater than M, and the first image processing unit further transmits image data of a first region of the plurality of regions to the second image processing unit; wherein the first image processing unit determines whether to transmit image data of a second region different from the first region of the plurality of regions to the second image processing unit according to a bandwidth of a transmission medium between the first and second image processing units.