1. An image processing method of processing image portrayal information used for rendering by attaching textures, the method comprising: separating a texture area to which the texture is attached and a non-texture area to which the texture is not attached in a coordinate system of a rendering-completed image represented by the image portrayal information; compressing the image portrayal information of the non-texture area by a first compression method; and compressing the image portrayal information of the texture area by a second compression method different from the first compression method.