An image processing device includes circuitry. The circuitry reads YUV image data for each block of a predetermined size; performs discrete wavelet transform on a Y value of a pixel included in a block to obtain a first transformed Y value; multiplies the first transformed Y value by a coefficient used for inversely transforming the first transformed Y value, to calculate a second transformed Y value; and quantizes a U value and a V value included in the block and the second transformed Y value to generate fixed length encoded data.