To provide an image processing system wherein traffic of a network is reduced, the link operation is normally operated without decreasing the speed, the image memory consumption by a slave side is minimized, and other image processing process can be operated by using a sufficient image memory capacity.

The image processing system wherein image data are transferred between one image processor being a transfer sender of image data and one or a plurality of image processors being transfer destinations of the image data, is provided with a control means 13 that splits image data for one page on the image processor being the transfer sender into a plurality of blocks with a fixed size, applies color conversion to each split block, and inhibits transfer of a color component of the image data of the split block when an absolute value of a color difference component after the color conversion in all pixels in the split block is a prescribed threshold or below (function of a color image decision circuit 23).