There are provided an image generating system and program which can generate an image of an object variable in its state depending on an impacted position, in real-time with less amount of data and reduced load in computation. The image generating system generates an image of an aggregate object formed by a plurality of part objects. The image generating system comprises: an object determination section (120) which determines part objects within a predetermined area in the aggregate object as objects to be changed in display form when an impact is applied to the aggregate object and the impacted position is included within the predetermined area; and an image generation section (160) which changes at least one of shape, color, position, rotation angle, direction, moving direction and moving speed of the part objects determined as objects to be changed and generates an image. The aggregate object may be formed by assembling a plurality of part objects having different shapes without any gaps. The image of the aggregate object may be generated as an image of a single object before the impact is applied thereto and as an image of an aggregate object after the impact.