opt-jpg(1) General Commands Manual 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)] [-t(ouch)] 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 programs (image
viewers, web browsers, image editors) might not read them
successfully. 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 icc Copy only ICC profile markers. Identical to "-copy icc" 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.
-t Preserve timestamp on modified files.
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 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) 2004-2023 by Brian Lindholm. This program is free
software; 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
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
littleutils 2023 Mar 25 opt-jpg(1)
littleutils 1.2.6 - Generated Mon Jun 26 07:56:58 CDT 2023