An image processing system is disclosed that includes a superimposing merger operation unit. The superimposing merger operation unit receives the encoded data of a main image and the encoded data of a sub image, and generates superimposedly merged encoded data by merging the encoded data of the main and sub images superimposedly. The superimposedly merged encoded data generated by the superimposing merger operation unit is configured so that the main image is stored therein and that when the superimposedly merged encoded data is decoded, each of the main image and sub image is reproduced with the sub image being reproduced superimposedly with respect to the main image.