An object attribute is determined with respect to an object and a determination is performed as to whether or not to execute image cache processing in response to the object attribute. By switching processing in accordance with this, execution of time-consuming image specifying processing is kept to a necessary minimum and performance reductions can be avoided. Furthermore, cache registration is avoided for images having low reusability, which achieves improvements in cache usage efficiency and improvements in cache search efficiency, thereby enabling performance to be improved.