Projects / jpegoptim


jpegoptim is a utility for optimizing JPEG files. It provides lossless optimization (based on optimizing the Huffman tables) and "lossy" optimization based on setting a maximum quality factor.

Operating Systems

Recent releases

  •  28 May 2014 07:40

    Release Notes: This release fix the --stdin option (assume -f when reading from stdin) and other minor issues.

    •  15 May 2014 04:30

      Release Notes: Memory is now used instead of temporary files during optimization. Support for reading input from stdin (and sending output to stdout) was added. There were other minor enhancements and fixes.

      •  21 Apr 2014 07:08

        Release Notes: Many minor fixes and enhancements, including XMP marker support.

        •  20 Mar 2013 07:28

          Release Notes: Support for progressive JPEGs has been added (fixes a long standing "bug" of progressive JPEGs becoming non-progressive during optimization). New options --all-normal and --all-progressive for converting JPEGs to non-progressive and progressive. A new -S / --size option to set the target size for the output file.

          •  14 Mar 2013 06:03

            Release Notes: Safer temp file handling (if mkstemps() is available, and a patch to make "quiet mode" (-q) be quiet.

            Recent comments

            15 Sep 2011 09:45 scamp3

            Hi Timo Kokkonen,

            I'd like to suggest a new option to jpegoptim: the adaptive (dynamic) Huffman coding.

            After reading this paper:


            it turns out that the usual custom Huffman table (also called optimized JPEG) yields on average a reduction of 1.38% of image's size, but the use of dynamic Huffman coding (which builds an even better Huffman table) almost doubles this figure by yielding on average a further reduction of 1.01%.

            An implementation of Vitter's algorithm (an improved version of the algorithm mentioned in the previous paper and which yields even better reductions) is released in the public domain and can be found here :


            Given all this, would it be possible to add this new option to jpegoptim to optimize baseline and progressive JPEGs?


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