pngnq - quantize png images

       Stuart Coyle <stuart.coyle@gmail.com>

       Does  not  deal  correctly  with  greyscale alpha images with low bit depths, but these wont benefit from
       quantizing.

pngnq  quantizes  a  32-bit RGBA PNG image to an 8 bit RGBA palette PNG using the neuquant algorithm. The
       output file name is the input file name extended with "-nq8.png" or a specified extension.

       The "input files" defaults to standard input if not specified. If standard input is being  processed  the
       output is sent to standard output.

       pngnq - quantize png images

       -d dir Tells pngnq to put output files in a directory other than the one the input files are in.

       -e extension
              Specifies  the new filename extension. Defaults to "-nq8.png".  Pngnq drops .png from the original
              filenames. If you set the argument of the -e option to .png and choose the  -f  option  the  input
              file will be overwritten.

       -f     Force overwriting of files.

       -g gamma
              Set the image gamma correction. If not present, uses the png file's gamma or defaults to 1.0.

       -h     Print program help.

       -n colors
              Specifies  the number of colors to quantize to. Defaults to 256 which is the maximum.  The minimum
              here is 2.

       -Q dither
              Choose a dithering method: n = no dither (default), f = Floyd Steinberg dithering.

       -s sample factor
              Sample factor. The neuquant algorithm samples pixels stepping by this value.  The default value of
              3 gives good results. Higher values sample less of the image pixels and thus are faster  but  less
              accurate. A factor of 1 samples every image pixel.

       -v     Verbose mode. Prints status messages.

       -V     Print version number and library versions.

png(5)

Linux                                               MAY 2009                                            PNGNQ(1)

pngnq[-vfhV][-ssample_factor][-Qdither][-ggamma][-eextension][-ddir][-ncolors][inputfiles]