JPEGrescan: losslessly shrink any JPEG file.
Perl
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README.md

JPEGrescan: losslessly shrink any JPEG file

JPEGrescan is a perl script that uses jpeg tools to optimise jpeg compression by micro-managing some of the compression math based on research into some of the most common parameters.

NB: MozJPEG has the same optimisation built-in and is faster, so we recommend using MozJPEG when possible.

Usage

$ jpegrescan in.jpg out.jpg

Arguments

  • -s: Removes all Exif data and now all JFIF data as well. A basic 18-byte JFIF segment is added in its place.
  • -i: Allows optimisations that may be "incompatible" with some software. Currently this means removing all JFIF data (saving 18 bytes) and allowing an encoding not supported by Opera before version 11.61.
  • -t: Turns on multithreaded operation. Usually, uses up to 4 threads. Faster, but not four times faster than without -t. So try xargs -n1 -P to shrink a large number of jpegs at the same time.
  • -a: Turns on arithmetic coding. Note this is unsupported by most software.
  • -v: Verbose output.
  • -q: Suppress all output.

Package Availability

JPEGrescan is known to be packaged in the following distributions:

  • Arch's User Repository
  • NixOS

Issues

  • No out.jpg. Install the following:
    • Fedora: yum -y install perl-File-Slurp libjpeg-turbo-utils
    • Debian: aptitude install -y libfile-slurp-perl libjpeg-turbo-progs

Thanks

First, thanks to Loren Merritt who created this script originally. Also, thanks to the people on devshed and lyncd - whose names seem to be lost to the sands of time - who came up with the jfifremove idea and the basic C code.