MNG is closely related to the PNG image format. When PNG development started in early 1995, developers decided not to incorporate support for animation, not least because this feature of GIF was seldom 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 January 312001.
Software that supports MNG
MNG is currently not as widely supported as PNG. Nonetheless, Konqueror has native MNG support, and MNG plugins are available for most other web browsers. Mozilla browsers and Netscape 6.0, 6.01 and 7.0 included native support for MNG until the code was removed in 2003 due to code size and little actual usage, causing complaints on the Mozilla development site. As a result, a MNGzilla project was started to offer patched Mozilla and Firefox browsers. Neither Internet Explorer nor Safari currently support MNG. Recent Sony Ericsson phones support MNG files in their themes.
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. However, with the expiry on LZW patents and existence of alternative file formats such as Flash and SVG, combined with lack of MNG supporting viewers, web usages were far less than expected.
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, just as the SVG standard offers the "SVG Basic" and "SVG Tiny" subsets.
MNG does not yet have a registered MIME media type, but video/x-mng or image/x-mng can be used.
MNG animations may be included in HTML pages using the tag.
MNG can either be lossy or lossless, depending whether the frames are encoded in PNG (lossless) or JNG (lossy).