JPEGOPTIM(1) User Commands JPEGOPTIM(1)

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

-w<max>, --workers=<max>
Set the maximum number of parallel processes to launch.
(Default is 1)


-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 assumed 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.


--files-stdin
Read names of files to process from standard input. One
filename per line.


--files-from=<filename>
Read names of files to process from a file. One filename per
line.

METADATA OPTIONS

By default jpetoptim will keep common metadata (JPEG markers) and
discard any other (unknown 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 additional 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, --keep-all
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-jfif
Strip JFIF markers from output file.

--strip-jfxx
Strip JFXX (JFIF Extensions) markers 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-jfif
Do not strip any JFIF markers from output file.

--strip-jfxx
Do not strip any JFXX (JFIF Extensions) markers 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) 1996-2023 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.

4th Berkeley Distribution 21 Jun 2023 JPEGOPTIM(1)