Provided by: jpegoptim_1.4.7-1_amd64 
NAME
jpegoptim - utility to optimize/compress JPEG/JFIF files.
SYNOPSIS
jpegoptim [ options ] [ filenames ]
DESCRIPTION
jpegoptim 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 optimized), 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 optimization 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 optimization 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 original 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 convert all input files
to non-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.
--all-arith
Force all output files to use Arithmetic Coding. This option is experimental and
only available if jpegoptim was compiled with Arithmetic Coding support enabled.
--all-huffman
Force all output files to use (traditional) Huffman coding. This option is
experimental and only available if jpegoptim was compiled with Arithmetic Coding
support enabled.
--nofix
Skip processing of any input files that have any errors/warnings during
decompression. By default jpegoptim will attempt to optimize any file that it is
able to decompress, even if decompression generates warnings. This will 'fix' some
(corrupt) JPEG images automatically. If this behaviour is not desired, this option
can be used to make jpegoptim to skip any input files that contain any errors.
--stdout
Send output image to standard output. Note, if optimization didn't create smaller
file than the input file, then no output original image is passed through unmodified
(except any extra data after JPEG image will be discarded).
--stdin
Read input image from standard input and send output to standard output (--stdout is
assumend when this option is used). When this option is used then only one image is
read from standard input. 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.
METADATA OPTIONS
By default jpetoptim will keep common metadata (JPEG markers) and discard any other
(unkown ones).
Following markers are kept by default:
- EXIF
- IPTC
- ICC
- XMP
- COM (JPEG Comment markers)
JFIF marker will be regenerated (by libjpeg) during the process (this cannot be changed).
However, Adobe marker is also generated (or omitted) by libjpeg based on the image
colorspace, etc. This behavior depends on libjpeg library version being used. To make
sure Adobe marker is preserved option --keep-adobe can be used.
To remove additonal markers one or more the --strip-* options can be used.
For example: --strip-icc --strip-xmp --strip-com
Alternatively it is possible to specify --strip-all and then one or more of the --keep-*
options to explicitly list which markers to keep
For example: --strip-all --keep-exif --keep-iptc
Options for controlling metadata (markers) in output files:
-s, --strip-all
Strip all markers from output file. (NOTE! by default only Comment &
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.
NOTE! If this option is specified then any other --strip-* or --keep-* options are
ignored.
--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.
--strip-jfxx
Strip JFXX (JFIF Extensions) from output file.
--strip-Adobe
Strip Adobe markers from output file.
--keep-com
Do not strip any Comment (COM) markers from output file.
--keep-exif
Do not strip any EXIF markers from output file.
--keep-iptc
Do not strip any IPTC / Adobe Photoshop (APP13) markers from output file.
--keep-icc
Do not strip any ICC profiles from output file.
--keep-xmp
Do not strip any XMP profiles from output file.
--strip-jfxx
Do not strip any JFXX (JFIF Extensions) from output file.
--keep-Adobe
Do not strip Adobe markers from output file.
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 ALSO
jpeginfo(1)
AUTHOR
Timo Kokkonen <tjko@iki.fi>
COPYING
Copyright (C) 1996-2022 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 MERCHANTABILITY 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.