MNG Web Site

This is an open source project to develop a patch to restore MNG/JNG support to Mozilla. The output of the project will be a single patch or a set of patches that can be applied to the CVS trunk at Also, so long as MNG support is not enabled by default in the mozilla applications, this project will host MNG/JNG-enabled Mozilla and Firebird binaries for various platforms.

February 3, 2006:Separated the mng patch into one that adds the mng library and another (with trunk and branch versions) that adds mng "glue" to libpr0n and various configuration files. You need both the "add-libmng" patch and the appropriate "mng glue" patch. The "add-libmng" patch is not likely to be subject to bit-rot, while the "glue" patches will probably be updated frequently.

December 27, 2005:"mahowi" has started releasing "Firefox Community Edition" builds for Windows with MNG enabled and libpng disabled (i.e., libmng provides the PNG support). Some of these releases are available in the DOWNLOAD area.

December 4, 2005: we were asked by "pavlov" to stop updating the MNG patch at, bug #18574. The patches in the DOWNLOAD area here in will continue to be updated to keep up with merge conflicts.

September 4, 2005: The patch has been updated a number of times over the past few months just to keep up with incompatible changes that have been checked in to the CVS. Separate versions are being maintained for the trunk and MOZILLA_1_8_BRANCH.

February 3, 2005: Alexander Opitz uploaded a patch that uses libmng-1.0.9.

January 19, 2005: Gerard Juyn released libpng-1.0.9 which has some space optimization.

November 17, 2004: Alexander Opitz uploaded a patch that combines libimg2 and libmng-1.0.8, which saves about 60k due to double inclusion of the JPEG library.

August 18, 2004: A thread at MozillaZine has been opened to try to relieve the bugspam from bug #18574. Go to and rant and rave to your heart's content.

August 6, 2004: libmng 1.0.8 released. This add the specific data-push-mechanisms for Mozilla and Ogg Vorbis, and a few other bits & pieces.

July 7, 2004: Patch by Alexander Opitz. No known MNG bugs remain, although there is a problem with "many windows opening" if you apply the patch and then fail to build MNG support This does not seem to be a strictly MNG bug because you can also observe it by failing to build with JPEG or BMP support (UPDATE 7 Feb 05: A patch is available to fix this bug). It is possible to build with this patch and without libpng, to get PNG support via libmng, which saves about 40 kbytes.

March 21, 2004: libmng 1.0.7 released. This is mostly (again) in the light of size-reductions for the Mozilla integration. Also a couple of new canvas-styles have been added with the help of a few enthousiastic supporters!

March 16, 2004 UPDATE: To avoid trademark problems with, and any possible confusion with the "official" binaries, such binaries must not be called "Mozilla" or "FireFox"; therefore we will call them "Mngzilla" (the suite) or "MngFox" (the browser). We will use the same version numbers as the version of Mozilla or FireFox from which they were derived.

February 15, 2004 UPDATE: MngFox 0.8 binaries for Linux are available with MNG enabled. Get one from the [DOWNLOAD] area, in the "binaries-Linux->MngFox 0.8 (Nova)" package.

January 29, 2004 UPDATE: Linux installers are available for Mngzilla-1.7a (Languages en-US and de-AT). Get one from the [DOWNLOAD] area, in the "binaries-Linux->1.6+" package.

January 20, 2004 UPDATE: A patch is now available and has been tested with Mozilla-1.6.

November 3, 2003 UPDATE: A patch is now available and has been tested in building both Firebird 0.7+ and Mozilla-1.6a with MNG capability. Get it from the [DOWNLOAD] area, in the "Mngzilla->1.6a" package. Follow the instructions in the README.txt that is included in the distribution. Several binaries are also available in the [DOWNLOAD] area, courtesy of "Madman Nova" as well.

October 19, 2003: Libmng-1.0.6 released.

On June 3, 2003, MNG/JNG support was removed from the MNG trunk. See mozilla's bugzilla, bug #195280.

One objection to MNG was the size of the libmng library. Some progress has been made in this area, under bug #204520. We don't need to work on that here. This footprint-reduction work is included in libmng-1.0.6, which was released on October 19, 2003. See for CVS access to libmng or for a tar distribution of the libmng source.

Other history of the original development of MNG/JNG support for Mozilla, and the subsequent outcry upon its removal, can be found in bug #18574. The main problem now is the lack of an acceptable volunteer to maintain the "glue" code that links libmng to mozilla, which is found in the "libpr0n" module of Mozilla.

There are some MNG-restoration patches posted to bug #18574, but due to continued development of the mozilla trunk, they are no longer compatible and need to be revised (see comment #309 of bug #18574). This is partly due to the fact that PPM support was also removed around the same time (see bug #197530). They did however serve as the basis for the mngzilla project.

The SourceForge mngzilla project summary is here.

The SourceForge CVS for the mngzilla project is dormant. We are simply using the SourceForge File Distribution System.

The SourceForge mngzilla forums are here: [ Open Discussion] [ Help] [ Developers]

Here are the TODO.txt, README.txt, and ChangeLog.txt files.

The PNG, MNG, and JNG specifications are here.

Mngzilla is pronounced "ming zilla".


  • Files in the libimg/mng directory are licensed according to the libmng license, as are any new files that we might contribute to that directory, except for its mozilla-specific Makefile, which is under the Mozilla Public License.
  • Files in any other directories, and any new files that we might contribute to other directories, fall under the Mozilla Public License.

A list of relevant bugs from from is here.

This project was initiated on October 15, 2003, and is administered by Glenn Randers-Pehrson, glennrp at (formerly randeg at

Web and CVS space for this project are being provided by