
Jpegoptim v1.5.6 - Copyright (C)  Timo Kokkonen, 1996-2025. All Rights Reserved.


REQUIREMENTS
        Independent JPEG Group's jpeg library (libjpeg) version 6b or later.
        (Alternatively should also work with libjpeg-turbo or mozjpeg)


TESTED PLATFORMS
        Linux
        MacOS
        Windows (setargv.obj "link option" is needed for wildcards expansion to work)


INSTALLATION
        Installation should be very straightforward, just unpack the
        tar file, make necessary changes to the Makefile,  and then
        compile the program. You may wanna do something like this:

                tar xzvf jpegoptim-1.5.6.tar.gz
                cd jpegoptim-1.5.6
                ./configure
                make
                make strip
                make install


HISTORY
        v1.5.6 - add new option -r, --retry,
                 add new option --save-extra,
                 add new option --auto-mode,
                 processing image from standard input now behaves same like from a file,
                 other minor fixes
        v1.5.5 - improved JFIF handling (it should not longer get added
                 in some instances if it was not present in original),
                 new options --keep-jfif and --strip-jfif,
                 other minor fixes
        v1.5.4 - make sure JPEG mode (progressive vs non-progressive) is
                 preserved by default,
                 fix parallel processing when reading file list
                 (thanks to Cubittus)
        v1.5.3 - fix potential heap-buffer-overflow (read) when using
                 stdin/stdout and processing corrupt JPEG
        v1.5.2 - add support for reading list of files to process from a file
                 (--files-from) or from standard input (--files-stdin),
                 improved JPEG marker reporting,
                 fix -d, --dest option (thanks to Almas Kunapyanov),
                 other minor fixes
        v1.5.1 - fix logging to stdout when --stdout is used *thanks to Eta,
                 improved CMake support (and Github CI stuff) *thanks to Eta,
                 update --treshold option accept decimal numbers as parameter,
                 fix crashes when processing certain broken JPEG images,
                 fix memory leaks,
                 fix (logging) output in parallel processing mode
        v1.5.0 - add --workers=<max> option to enable parallel processing
                 fix --stdin option,
                 other minor fixes
        v1.4.7 - experimental support for arithmetic coding (enable with
                 configure option --with-arith),
                 add option --nofix,
                 add support for JFIF Extension (JFXX) markers,
                 support for nanosecond timestamps (thanks to GerbilSoft),
                 optimization now works same with stdin as with standard files,
                 fixed --size (-S) option not working correctly when processing
                 multiple files,
                 new --keep-* options to use with --strip-all (see man page),
                 other minor fixes
        v1.4.6 - fix double free introduced in previous release
        v1.4.5 - fix --overwrite option,
                 better error reporting for -d option,
                 fix memcmp() potentially reading past end of buffer,
                 some minor fixes
        v1.4.4 - more detailed error messages (thanks to Denis Fateyev),
                 CMake support (thanks to Ghostkeeper),
                 other minor fixes
        v1.4.3 - fix bug that could cause jpegoptim crash when processing
                 certain jpeg files
        v1.4.2 - add option -P, --preserve-perms,
                 some minor fixes
        v1.4.1 - fix --stdin option (assume -f when reading from stdin),
                 workaround to bug in libjpeg-turbo (v1.3.1) triggered
                 when option -V or --version was used,
                 other minor fixes
        v1.4.0 - use memory (instead of temporary files) during optimization,
                 support for reading input from stdin (and sending output to
                 stdout),
                 report also libjpeg version when --version option used,
                 new option --strip-none to preserve "all" markers,
                 other minor fixes & cleanup
        v1.3.1 - XMP marker support and new --csv option (by Matteo Croce),
                 use DESTDIR instead of INSTALL_ROOT (by Samuli Suominen),
                 changes to make compiling under Win32 and Win64
                 easier (thanks to Javier Gutiérrez),
                 preserve permissions of files being optimized,
                 skip symlinks (and other special files),
                 other minor fixes
        v1.3.0 - support for progressive jpegs added (fixes long standing
                 "bug" of progressive jpegs becoming non-progressive during
                 optimization),
                 new options --all-normal & --all-progressive for
                 converting jpegs to non-progressive & progressive,
                 new -S / --size option to set target size for output
                 file (enables lossy optimization),
                 updated GPL/Copyrights language (thanks to Nicolas Vieville)
        v1.2.5 - safer temp file handling (if mkstemps() available),
                 patch to make "quiet mode" (-q) be quiet by Mathieu Malaterre
        v1.2.4 - new -T / --threshold option by Matteo Croce,
                 minor fixes (potential memory leaks),
                 merged some patches from Debian jpegoptim package (1.2.3-2)
        v1.2.3 - IPTC marker support by Dustin Ward,
                 ICC profile support by Dwight Kelly,
                 minor fixes
        v1.2.2 - Now Exif and COM markers are not discarded
                 (all other markers are discarded as before).
                 New options --strip-all, --strip-exif, and --strip-com
                 added for controlling what markers to strip.
        v1.2.1 - fixed buggy temp file handling
        v1.2.0 - Added new options --overwrite and --preserve.
                 GNU autoconf support added, also.
        v1.1   - new -f option, and other minor changes, improved
                 support for other platforms
        v1.0a  - some changes in docs & makefile
        v1.0   - first public release



LATEST VERSION

        Latest version is always available from:
                http://www.iki.fi/tjko/projects.html

        Sources (GIT)
                https://github.com/tjko/jpegoptim


ACKNOWLEDGEMENT

        This software is based in part on the work of the Independent JPEG Group.


SPONSORS

Special thanks for following Github Sponsors that have supported jpegoptim:

 - midir99



Timo <tjko@iki.fi>
14-Sep-2025
