An image encoding method includes: generating a first bitstream by encoding an input image, and a first decoded image by encoding and decoding the input image; and generating a second bitstream by encoding the input image using the first decoded image, and a second decoded image by encoding and decoding the input image; wherein the second decoded image has resolution or image quality higher than resolution or image quality of the first decoded image, the generating of a second bitstream and a second decoded image includes generating a prediction block for a current block by intra prediction, and in the generating of a prediction block, the prediction block is generated using (i) pixels included in the second decoded image as top and left reference pixels for the current block, and (ii) pixels included in the first decoded image as right and bottom reference pixels for the current block.