MNG (pronounced ming) is a public file format for animated images. The name stands for Multiple-image Network Graphics.
MNG is closely related to the PNG image format. When PNG development started in early 1995, it was decided not to incorporate support for animation, not least of all because this feature of GIF was little used at the time. However, work soon started on MNG as an animation-supporting version of PNG.
Version 1.0 of the MNG specification was released on 31 January 2001. MNG is therefore very new, and is currently not as widely supported as PNG. Nonetheless several web browsers, Mozilla (removed in version 1.5a), Netscape and Konqueror, do already have native MNG support, and MNG plugins are available for Opera and Internet Explorer. The MNG developers hope that in time MNG will begin to replace GIF for animated images on the World Wide Web, just as PNG has already begun to do for still images.
The structure of MNG files is essentially the same as that of PNG files, differing only in the slightly different signature (8A 4D 4E 47 0D 0A 1A 0A in hexadecimal) and the use of a much greater variety of chunks to support all the animation features that it provides. Images to be used in the animation are stored in the MNG file as encapsulated PNG or JNG images.
Two versions of MNG of reduced complexity are also defined: MNG-LC (low complexity) and MNG-VLC (very low complexity). These allow applications to include some level of MNG support without having to implement the entire MNG specification.
MNG does not yet have a registered MIME media type, but video/x-mng can be used.
In an unfortunate turn, Mozilla has removed native support for MNG in version 1.5a and all future versions and does not seem inclined to replace it anytime soon, despite the community's objections. The Firebird plugin is the official "replacement"...
There is also an attempt to create a Mozilla variant that has MNG support included called MNGzilla.