Encoding/decoding in the decomposition and recomposition of a high resolution image

More efficient encoding/decoding in decomposing and decomposing a high resolution image is obtained by employing a unique pixel cluster arrangement. The pixel clusters of an image are classified as one of a plurality of classifications. A unique encoding/decoding technique is assigned to each classification. In one embodiment, a cluster including at least one high resolution pixel to be recomposed from a corresponding low resolution pixel which is a so-called exception to general prediction rules is classified as a first classification. A cluster including no pixels which are exceptions is classified as a second classification. Supplemental information is encoded/decoded for all pixels in a cluster classified as the first classification. Pixels in the cluster classified as the second classification are encoded/decoded according to the general prediction rules.