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JPEGOPTIM(1) General Commands Manual 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 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 re- duce 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 -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 origi- nal file. This is slightly less safe than the default mode of op- eration (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 re- placed. 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 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 com- piled 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 opti- mize any file that it is able to decompress, even if decompres- sion generates warnings. This will 'fix' some (corrupt) JPEG im- ages automatically. If this behaviour is not desired, this op- tion 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 in- put 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 dis- card 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 omit- ted) by libjpeg based on the image colorspace, etc. This behavior de- pends 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 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, --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 out- put 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 re- quested 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 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 21 Jun 2023 JPEGOPTIM(1)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | METADATA OPTIONS | BUGS | SEE ALSO | AUTHOR | COPYING
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