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opt-jpg(1)                                                          opt-jpg(1)




NAME

       opt-jpg - losslessly optimize JPEG image files


SYNOPSIS

       opt-jpg [ -a(rithmetic) ] [ -g(ray) ] [ -h(elp) ]
       [ -m markers_to_copy ] [ -q(uiet) ] file...


DESCRIPTION

       opt-jpg losslessly optimizes JPEG images.  This is accomplished using a
       combination of the filesize, jpegtran, and tempname utilities.


OPTIONS

       -a     Allow arithmetic coding to be used  on  re-written  image  files
              instead  of  the  more prevalent Huffman coding.  This can yield
              image files that are 5-7% smaller,  but  older  software  (image
              viewers,  web  browsers, image editors) might not read them suc-
              cessfully.  USE WITH CAUTION.

       -g     Force the output to grayscale.

       -h     Print help and quit.

       -m none
              Copy no markers from source file.   Identical  to  "-copy  none"
              option from jpegtran.  This is the default.

       -m comments
              Copy only comment markers.  Identical to "-copy comments" option
              from jpegtran.

       -m all Copy all extra markers.  Identical to "-copy  all"  option  from
              jpegtran.

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


EXAMPLES

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

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

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

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


NOTES

       This  program  may  create progressive JPEG files from images that were
       previously non-progressive.  Curiously, they are sometimes smaller.


SEE ALSO

       filesize(1), jpegtran(1), tempname(1)


COPYRIGHT

       Copyright (C) 2004-2012 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                       2012 Dec 12                       opt-jpg(1)

littleutils 1.0.29 - Generated Thu Aug 22 05:51:36 CDT 2013