An image generating system determines respective luminance values of multiple polygons representing a surface of a subject rendered by reference to a texture image attached to the multiple polygons. The system includes a capturing section storing a texture image of an object deformed by external force; a memory section retaining a correspondence table including information about a position of one polygon set corresponding to a position on a surface of the object to which no external force is applied, information about a stress vector indicating external force applied to the position on the surface of the object and associated with the one polygon corresponding to the position on the surface of the object to which external force is applied, and information about the luminance value of the texture image of the object to which the external force is applied; and a texture mapping section making reference to the table.