An image processing method including the following steps is provided. An image information of an image is received, wherein the image includes a plurality of blocks and the image information includes a plurality of pixel information of each block. A dual gamma correction is performed on a first group of blocks of the image to obtain one or more corrected blocks and the dual gamma correction is skipped on a second group of blocks of the image to obtain a plurality of uncorrected blocks. A first encoding process is performed on the one or more corrected blocks to obtain a plurality of first encoded blocks. A second encoding process different from the first encoding process is performed on the plurality of uncorrected blocks to obtain a plurality of second encoded blocks.