A method for image processing with encoding selection is provided. In accordance with the color pixel, the maximum pixel value, and the minimum pixel value, the corresponding encoding method is selected and encoding is performed for producing encoding data corresponding to the color pixel. The present invention further comprises a color-difference operation for selecting a plurality of color pixels as a basic pixel, a first color pixel, and a second color pixel. When encoding the basic pixel, a first color difference, and a second color difference, respectively, first encoding data corresponding to the basic pixel, second encoding data corresponding to the first color difference, and third encoding data corresponding to the second color difference are produced, respectively.