A compression and decompression module provided in a display device includes: a comparison unit that, when first image data and second image data in which a gradation value of each of a plurality of pixels is expressed in m bits are input, compares gradation values of corresponding pixels of the input first and second image data; a compression unit that compresses the second image data and that, when values of predetermined n bits (where n≦m) of the gradation values match each other in a comparison result of the comparison unit, generates compressed data including identification data indicating that the values of the n bits match each other; and a control unit that performs control to output data, which indicates the gradation value of the corresponding pixel of the first image data, and the compressed data generated by the compression unit so as to correspond to each other.