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, the creating of the main image includes reducing a size thereof in relation to an original size of the respective source moving image in accordance with a main image reduction ratio and the creating of the secondary image includes reducing a size thereof in relation to an original size of the respective source moving image in accordance with a secondary reduction ratio, in which the main image reduction ratio is different from the secondary reduction ratio, in which each of the main image reduction ratio and the secondary reduction ratio has a respective value so as to enable the main image and the secondary image to be sized such that the integrated image created therefrom has a size equivalent to that of the original size of the respective moving image, and in which the plurality of different source moving images represent right eye and left eye moving images, such that (i) a first respective main image is created for a respective right eye moving image and a first respective secondary image is created therefor from a respective differential image that expresses the difference between the respective right eye moving image from which the respective main image was created and another right eye moving image in a different frame and a first respective integrated image is created by combining the first respective main image and the first respective secondary image, and (ii) a second respective main image is created for a respective left eye moving image and a second respective secondary image is created therefor from a respective differential image that expresses the difference between the respective left eye moving image from which the second respective main image was created and another left eye moving image in a different frame and a second respective integrated image is created by combining the second respective main image and the second respective secondary image, and such that the value of the main image reduction ratio and that of the secondary reduction ratio enable (i) both the first respective main image and the first respective secondary image to be sized so that the size of the first respective integrated image created therefrom is equivalent to the original size of the respective right eye moving image and (ii) both the second respective main image and the second respective secondary image to be sized so that the size of the second respective integrated image created therefrom is equivalent to the original size of the respective left eye moving image.