Classified image from Envi in it's own format has default gray value based on zero to num_class-1, and there will be default colors defined for each class in the .hdr file. But supposed coding the grayValue in this way, for example: 0, 14, 168, 22, 246, 279, 34, 379.  And now how should assign colors for each class ,as well as save the  image in tiff format. Who have good ideas?