Projects / pngcrush


pngcrush is an excellent batch-mode compression utility for PNG images. Depending on the application that created the original PNGs, it can improve the file size anywhere from a few percent to 40% or more (completely losslessly). The utility also allows specified PNG chunks (e.g. text comments) to be inserted or deleted, and it can fix incorrect gamma info written by Photoshop 5.0 as well as the erroneous iCCP chunk written by Photoshop 5.5.


Recent releases

  •  16 Mar 2014 02:20

    Release Notes: Fixes a bug with reducing 16-bit images to 8-bit using the "-reduce" option. Restores calls to png_set_crc_action(), which had been removed from version 1.7.72 for some testing and inadvertently not restored. Adds code to fix/salvage PNG files with a "bad adaptive filter value" error. Avoids calculating CRC during compression trials except for the last trial, when the output is actually written.

    •  08 Feb 2014 14:36

      Release Notes: The bundled static libpng has been updated to version 1.6.9.

      •  18 Jul 2013 22:08

        Release Notes: This release fixes a bug with the new "-reduce" option which would remove the alpha channel even when it was not all-opaque.

        •  09 Mar 2013 16:43

          Release Notes: This release fixes a bug introduced in 1.7.52 which caused the -reduce option to produce a tRNS chunk which had more entries than the PLTE chunk (which is invalid).

          •  05 Mar 2013 16:41

            Release Notes: This release fixes initialization problems introduced in version 1.7.51, reinitializes settings before processing each file, and makes the "-reduce" option work properly.

            Recent comments

            12 Jul 2002 19:37 ivan5242

            Great program.
            This is excellent.

            29 Jul 2000 12:49 phlinex

            libPNG example
            I would prefer this as a second libPNG example... Pefect to demonstrate.


            08 Dec 1999 18:11 glennrp

            Version 1.2.2 will include a rudimentary makefile for people
            who don't want to type

            gcc -O -o pngcrush *.c

            07 Dec 1999 11:37 shaman

            Badly needs a makefile or configure script.


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