An encoding method may comprise obtaining a residue corresponding to a difference between the original image and a prediction image with respect to each component of the original image, encoding the residue of a predetermined component of the original image, restoring the encoded residue of the predetermined component and transforming the restored residue into a predetermined value including the restored residue value, and encoding prediction residues corresponding to differences between each of residues of components of the original image, which are not encoded, and the residue, which is restored and transformed into the predetermined value. Since prediction residues are encoded and decoded using correlations between residues of image components and image components, data amount is highly reduced. Also, since there is no quality loss in a picture generated by directly encoding an R-G-B image without transforming it into a Y-Cr-Cb image, high quality image information is obtained.