1. An image generation system which generates or edits an image using a plurality of image generation devices, comprising: a division unit dividing a target image into a plurality of divided images; a providing unit providing a reference image corresponding to the target image to be displayed on the plurality of image generation devices; a distribution unit distributing a plurality of divided images obtained by said division unit to corresponding image generation devices, and distributing the reference image to the image generation devices; a display unit displaying the divided image and the reference image in the image generation device; and an integration unit integrating divided images generated or edited by the plurality of image generation devices.