A client apparatus checks overlap of graphic objects described in multimedia description data. For an image found to be not overlapped with another graphic object, the client apparatus transmits a whole image request for whole image data to a server apparatus. For an image found to be overlapped with another graphic object, the client apparatus determines one or more partial images, and transmits a partial image data request corresponding to each determined partial image. The client apparatus receives the whole image data or partial image data returned from the server apparatus in response to the request, and generates a layout image described by the multimedia description data by using the received whole image data or partial image data.