1. A method for encoding an image, the method comprising: generating at least one prediction group by grouping a plurality of prediction schemes; generating at least one orthogonal transform group by grouping a plurality of orthogonal transform schemes; matching the at least one prediction group to the at least one orthogonal transform group; and encoding an input image, based on the matching, by transforming a block predicted by a prediction scheme of a predetermined prediction group using an orthogonal transform scheme of an orthogonal transform group, which is matched to the predetermined prediction group.