Disclosed is an image encoding method in which a series of decoded images are generated from a series of original images with the aid of a first encoding process. Furthermore, a series of second images are generated from an image group of the series of original images with the aid of an INTER encoding mode of the second encoding process, at least one decoded image being used as a reference image. The reference image represents an original image area is to be encoded. A image decoding method decodes second images generated by the image encoding method.