PNG Reference Library: libpng
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.
The primary web site for PNG is www.libpng.org/pub/png.
The primary public ftp site for libpng is
The previous ftp site is still being maintained at ftp://ftp.simplesystems.org/pub/png, but the OSUOSL site is much faster and has a more complete archive of old versions.
The ftp site for beta versions of libpng is also at ftp://ftp-osl.osuosl.org/pub/libpng/src/beta
The current public and beta versions of libpng are also available at https://sourceforge.net/project/showfiles.php?group_id=5624.
There are pointers to various distributions of libpng and MD5 checksums here.
You can receive notifications of libpng releases through release-monitoring.org, at release-monitoring.org/projects/search/?pattern=libpng.
The Sourceforge project page for libpng is at https://sourceforge.net/projects/libpng/
A "git" repository for libpng is available. You can access it by cloning git://git.code.sf.net/p/libpng/code or you can browse it at github.com/glennrp/libpng. or at sourceforge.net/p/libpng/code. At present, there are eight branches:
The "master" branch 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 fossies.org/libpng.
An "ABI compatibility analysis" of libpng releases is available at abi-laboratory
The Coverity project for libpng is at https://scan.coverity.com/projects/4061. The project is set up to scan the head of each of the libpng10 through libpng17 branches (libpng00 is not included). As of December 3, 2015, libpng-1.0.65, libpng-1.2.55, libpng-1.4.18, libpng-1.5.25, libpng-1.6.20, and libpng-1.7.0beta70 were all reported to be defect-free).
The mailing list for libpng developers and developers of libpng-based applications is png-mng-implement (at) lists.sourceforge.net. Visit http://png-mng.sourceforge.net/pub/png/pngmisc.html#lists to subscribe. (archived here)
If you wish to privately report a security issue (vulnerability) in libpng, please report it by email to png-mng-security at lists.osuosl.org, where it will be seen by a small group of long-time libpng contributors. You don't need to subscribe (in fact you probably won't be allowed to subscribe) to that list. If all else fails, you may send email to glennrp at gmail dot com or to glennrp at comcast dot net.
Feel free to download and use the official PNG logo (size 88x31) with your application documentation and web pages:
This site belongs to the PNG Development Group and is maintained for
the group by Glenn Randers-Pehrson
glennrp at users.sourceforge.net
Web space for this project is being provided by sourceforge.net