An image compression method includes at least the following steps: receiving a plurality of pixels of a frame, wherein pixel data of each pixel has a plurality of color channel data corresponding to a plurality of different color channels, respectively; encoding the pixel data of each pixel and generating bit-streams corresponding to the plurality of color channel data of the pixel, wherein the bit-streams corresponding to the plurality of color channel data of the pixel are separated; packing bit-streams of a same color channel data of different pixels into color channel bit-stream segments, wherein each of the bit-stream segments has a same predetermined size; and concatenating color channel bit-stream segments of the different color channels into a final bit-stream. Alternatively, color channel bit-stream segments of the same pixel are concatenated into a concatenated bit-stream portion, and concatenated bit-stream portions of different pixels are concatenated into a final bit-stream.