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opt-png(1)                                                          opt-png(1)




NAME

       opt-png - losslessly optimize PNG image files


SYNOPSIS

       opt-png  [-g(ray)] [-h(elp)] [-q(uiet)] [-r(es) DPI] [-t(ouch)] file...


DESCRIPTION

       opt-png losslessly optimizes PNG  images  by  removing  unused  palette
       entries  and/or  optimizing  the  filtering  algorithm.  This is accom-
       plished using a combination  of  the  filesize,  pngcrush,  pngrecolor,
       pngstrip, and tempname utilities.


OPTIONS

       -g     Force output to grayscale.

       -h     Print help and quit.

       -q     Quiet output.  No output commentary will be printed.

       -r DPI Write the specified resolution into the pHYs chunk of the output
              file.  Units are in pixels-per-inch.  To  convert  from  pixels-
              per-meter,  multiply  by 0.0254 (or divide by 39.37).  Note that
              this does not change the number of pixels in the image.  It only
              changes the assumed size of the pixels.

       -t     Preserve timestamp on modified files.


EXAMPLES

       Optimize a couple of image files:
              opt-png image001.png image002.png

       Optimize all PNG images in an entire directory tree:
              find . -name "*.png" -exec opt-png {} \;

       Or alternatively, optimize all PNG images this way:
              find . -name "*.png" -print0 | xargs -0 opt-png

       Fully utilize a quad-core system while optimizing all PNG images:
              find . -name "*.png" -print0 | xargs -0 -n 1 -P 4 opt-png
              find . -name "*.png" | parallel opt-png


NOTES

       If  at  all possible, make sure that pngcrush version 1.6.x or later is
       running  on  your  computer.  It  performs  substantially  better  than
       pngcrush  1.5.10 (and earlier) on black-and-white (and other low-color)
       images due to use of the Z_RLE zlib strategy.


SEE ALSO

       filesize(1), pngcrush(1), pngrecolor(1), pngstrip(1), tempname(1)


COPYRIGHT

       Copyright (C) 2004-2020 by Brian Lindholm.  This program is free  soft-
       ware; you can use it, redistribute it, and/or modify it under the terms
       of the GNU General Public License as published  by  the  Free  Software
       Foundation; either version 3, or (at your option) any later version.

       This  program  is  distributed  in the hope that it will be useful, but
       WITHOUT ANY  WARRANTY;  without  even  the  implied  warranty  of  MER-
       CHANTABILITY  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
       Public License for more details.



littleutils                       2020 Oct 19                       opt-png(1)

littleutils 1.2.3 - Generated Thu Dec 3 07:41:27 CST 2020
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