The present invention enables the high speed processing of a foreground component image and a background component image associated with images received on a network platform. A client computer outputs information specifying image data to a separation server. The separation server then obtains the specified image data from a storage server and outputs it to a motion detecting server to perform motion detection processing. Thereafter, the image data, a motion vector, and positional information are output to an area specifying server. The area specifying server generates area information corresponding to the image data and outputs the area information to a mixture ratio calculating server in addition to the image data, the motion vector, and the positional information. The mixture ratio calculating server then calculates a mixture ratio on the basis of the image data, the motion vector, the positional information, and the area information, whereby a foreground/background image separation server separates the foreground and background of the input image on the basis this information.