JPEGOPTIM(1)JPEGOPTIM(1)NAMEjpegoptim - utility to optimize/compress JPEG/JFIF files.
SYNOPSISjpegoptim [ options ] [ filenames ]
DESCRIPTIONjpegoptim is used to optimize/compress jpeg files. Program supports
lossless optimization, which is based on optimizing the Huffman tables.
And so called "lossy" optimization where in addition to optimizing
Huffman tables user can specify upperlimit for image quality.
NOTE! By default jpegoptim modifies the input files (if they are opti‐
mized), to preserve original files use option -d to specify alternate
directory for saving the optimized files to.
Only normal files are optimized (symbolic links and special files are
skipped). Also, any other hard links to the file being optimized (as
created using link(2)) are unaffected.
OPTIONS
Options may be either the traditional POSIX one letter options, or the
GNU style long options. POSIX style options start with a single ``-'',
while GNU long options start with ``--''.
Options offered by jpegoptim are the following:
-d<path>, --dest=<path>
Sets alternative destination directory where to save optimized
files (default is to overwrite the originals). Please note that
unchanged files won't be added to the destination directory. This
means if the source file can't be compressed, no file will be
created in the destination path.
-f, --force
Force optimization, even if the result would be larger than the
original file.
-h, --help
Displays short usage information and exits.
-m<quality>, --max=<quality>
Sets the maximum image quality factor (disables lossless opti‐
mization mode, which is by default enabled). This option will
reduce quality of those source files that were saved using higher
quality setting. While files that already have lower quality
setting will be compressed using the lossless optimization
method.
Valid values for quality parameter are: 0 - 100
-n, --noaction
Don't really optimize files, just print results.
-S<size>, --size=<size>
Try to optimize file to given size (disables lossless optimiza‐
tion mode). Target size is specified either in kilobytes (1 - n)
or as percentage (1% - 99%) of the original file size.
-T<threshold>, --threshold=<threshold>
Keep the file unchanged if the compression gain is lower than the
threshold (%).
Valid values for threshold are: 0 - 100
-b, --csv
Print progress info in CSV format.
-o, --overwrite
Overwrite target file even if it exists (when using -d option).
-p, --preserve
Preserve file modification times.
-P, --preserve-perms
Preserve file permissions (owner/group) by overwriting the origi‐
nal file. This is slightly less safe than the default mode of
operation (where new file is first saved as temporary file and
then renamed over the original file). In this mode a backup of
the original file is made with .jpegoptim.bak extension, and this
file is removed after the original file has been successfully
replaced. NOTE! if running jpegoptim as root there is generally
no need to use this option, as jpegoptim is able to preserve file
permissions when run by root in default mode.
-q, --quiet
Quiet mode.
-t, --totals
Print totals after processing all files.
-v, --verbose
Enables verbose mode (positively chatty).
--all-normal
Force all output files to be non-progressive. Can be used to con‐
vert all input files to progressive JPEGs when used with --force
option.
--all-progressive
Force all output files to be progressive. Can be used to convert
all normal (non-progressive) JPEGs input files to progressive
when used with --force option.
-s, --strip-all
Strip all markers from output file. (NOTE! by default only Com‐
ment & Exif/IPTC/PhotoShop/ICC/XMP markers are kept, everything
else is discarded). Output JPEG still likely will contains one
or two markers (JFIF and Adobe APP14) depending on colorspace
used in the image, as these markers are generated by the libjpeg
encoder automatically.
--strip-none
Preserve "all" markers in the image. This will leave all markers
untouched in the image, except JFIF (APP0) and Adobe (APP14)
markers as those get regenerated by the libjpeg library.
--strip-com
Strip Comment (COM) markers from output file.
--strip-exif
Strip EXIF markers from output file.
--strip-iptc
Strip IPTC / Adobe Photoshop (APP13) markers from output file.
--strip-icc
Strip ICC profiles from output file.
--strip-xmp
Strip XMP profiles from output file.
--stdout
Send output image to standard output. Note, if optimization
didn't create smaller file than the input file, then no output
(image) is sent to standard output. (Option -f can be used to
force output of image always, even if optimized image was not
smaller than input).
--stdin
Read input image from standard input. When this option is used
then only one image is read from standard output. Any (other)
input files specified on command line are ignored. Note, if
input file '-' is seen on command line then standard input is
also assumed.
Currently this option will explicitly enable -f option, thus out‐
put image is always sent to standard output (even if no optimiza‐
tion was possible).
BUGS
When using --size option, resulting file is not always exactly the
requested size. Workaround is to re-run jpegoptim on the same file
again which often will result file closer to target size.
SEE ALSOjpeginfo(1)AUTHOR
Timo Kokkonen <tjko@iki.fi>
COPYING
Copyright (C) 1996-2015 Timo Kokkonen
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, 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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
4th Berkeley Distribution 28 Nov 2014 JPEGOPTIM(1)
