PNG Reference Library: libpng

PNG Web Site


This is an open source project to develop and maintain the reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files.

UPDATE 12 November 2015:

  • The latest released versions are libpng-1.5.24 and libpng-1.6.19 [DOWNLOAD].

  • For legacy applications, libpng-1.4.17, libpng-1.2.54, and libpng-1.0.64 are also available and will only be updated if necessary for security reasons.

UPDATE 26 November 2015: The latest development versions are libpng-1.2.55rc01, libpng-1.4.18rc01, libpng-1.5.25rc01, libpng-1.6.20rc01 and libpng-1.7.0beta69 [DOWNLOAD]. libpng17 has 8-bit compose and rgb_to_grayscale accuracy improvements, and a new "affirm" (similar to "assert()") bug reporting system.

The primary web site for PNG is

The primary public ftp site for libpng is

The ftp site for beta versions of libpng is

The current public and beta versions of libpng are available at

There are pointers to various distributions of libpng and MD5 checksums here.

The Sourceforge project page for libpng is at

A "git" repository for libpng is available. You can access it by cloning git:// or you can browse it at or at At present, there are eight branches (libpng00, libpng10, libpng12, libpng14, libpng15, libpng16, libpng17, and a "master" branch which is roughly equivalent to the "libpng16" branch). Development occurs in the "libpng16" and "libpng17" branches; parts of the new developments are also ported to the "libpng15" branch; the rest are just for legacy and security purposes.

A "doxygen" index for various releases is available at

A "compatibility analysis" of libpng releases through 1.6.18beta09 is available at (service discontinued July 21, 2015).

The Coverity project for libpng is at The project is set up to scan the head of each of the libpng10 through libpng17 branches (libpng00 is not included). As of November 12, 2015, libpng-1.0.64, libpng-1.2.54, libpng-1.4.17, libpng-1.5.24, libpng-1.6.19, and libpng-1.7.0beta68 were all reported to be defect-free).

The mailing list for libpng developers and developers of libpng-based applications is png-mng-implement (at) Visit to subscribe. (archived here)

Bug reports can be sent to the mailing list or submitted via the SourceForge Bug tracker (select the "Create Ticket" button).

Feel free to download and use the official PNG logo (size 88x31) with your application documentation and web pages:

pngbar.png pngbar.png pngbar.jpg pngbar.jpg
Both pngbar.tar.gz Both

This site belongs to the PNG Development Group and is maintained for the group by Glenn Randers-Pehrson glennrp at

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