1. An image transmission method, comprising the steps of: inputting a plurality of different source moving images sequentially; creating a main image for each frame from one of the plurality of different source images; creating a secondary image for each frame from a differential image that expresses the difference between the source moving image from which the main image was created and another source moving image in a different frame; creating an integrated image by combining the main image and the secondary image; and transmitting the integrated image to a receiving side.