Abstract: A filing method and a system for filing image data operate to divide an input image having a dot number larger than a predetermined dot number of a display screen at a fundamental unit equal to the display screen size, to file the divided input images as a plurality of partial image data on an optical disk, and to retrieve the filed images at high speed. The division filing system includes an input image process device for compressing the divided partial image data, and an index generating device, such as a complexity detecting circuit, for extracting either position information of a distinguishable partial image, or address information among the divided partial images. An optical disk device stores either the position information or the address information as well as the compressed image data into an optical disk.