ppmqvga - 8 plane quantization

       Original by Lyle Rains (lrains@netcom.com) as ppmq256 and ppmq256fs combined, documented, and enhanced by
       Bill Davidsen (davidsen@crd.ge.com)

       Copyright  1991,1992  by Bill Davidsen, all rights reserved.  The program and documentation may be freely
       distributed by anyone in source or binary format. Please clearly note any changes.

                                                      local                                           PPMQVGA(1)

ppmqvga  quantizes  PPM  files to 8 planes, with optional Floyd-Steinberg dithering.  Input is a PPM file
       from the file named, or standard input of no file is provided.

   Options-d dither. Apply Floyd-Steinberg dithering to the data

       -q quiet. Produces no progress reporting, and no terminal output unless and error occurs.

       -v verbose. Produces additional output describing the number of colors found, and some information on the
       resulting mapping. May be repeated to generate loads of internal table output, but generally only  useful
       once.

       Error messages if problems, various levels of optional progress reporting.

       ppmqvga -d my_image.ppm | ppmtogif >my_image.gif

       tgatoppm zombie.tga | ppmqvga | ppmtotif > zombie.tif

       none known.

       ppmqvga - 8 plane quantization

       ppmquant

       ppmqvga [ options ] [ input file ]