1. An encoding device comprising: a compatible image encoding unit that generates a first encoded stream by designating a compatible image from a multi-viewpoint image and encoding the designated compatible image; an image converting unit that lowers the resolution of an auxiliary image that is used when the multi-viewpoint image is generated from the compatible image; an auxiliary image encoding unit that generates a second encoded stream by encoding the auxiliary image of which the resolution is lowered by the image converting unit; and a transmission unit that transmits the first encoded stream generated by the compatible image encoding unit and the second encoded stream generated by the auxiliary image encoding unit.