|Internet media type|
|Developed by||PNG Development Group (donated to W3C)|
|Type of format||computer animation|
|Container for||PNG, JNG|
Multiple-image Network Graphics (MNG) is a graphics file format, published in 2001, for animated images. Its specification is publicly documented and there are free software reference implementations available.
MNG is closely related to the PNG image format. When PNG development started in early 1995, developers decided not to incorporate support for animation, because the majority of the PNG developers felt that overloading a single file type with both still and animation features is a bad design, both for users (who have no simple way of determining to which class a given image file belongs) and for web servers (which should use a MIME type starting with image/ for stills and video/ for animations—GIF notwithstanding). 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.
Gwenview has native MNG support. GIMP can export images as MNG files. Imagemagick can create a MNG file from a series of PNG files. With the MNG plugin, Irfanview can read a MNG file. If MPlayer is linked against libmng, it and all its graphical front-ends like Gnome MPlayer can display MNG files.
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. Mozilla later added support for APNG as a simpler alternative. Similarly, early versions of the Konqueror browser included MNG support but it was later dropped. MNG support was never included in Google Chrome, Internet Explorer, Opera, or Safari.
|Irfanview||Partial, via plugin|
The MNG developers had hoped that MNG would replace GIF for animated images on the World Wide Web, just as PNG had done for still images. However, with the expiration of LZW patents and existence of alternative file formats such as APNG, Flash and SVG, combined with lack of MNG-supporting viewers and services, web usage was 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, where
4D 4E 47 is ASCII for "MNG" – see Portable Network Graphics: File header) 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 can either be lossy or lossless, depending whether the frames are encoded in PNG (lossless) or JNG (lossy).
The most common alternatives are Animated GIF and – up until its deprecation in 2017 – Adobe Flash, with the relative newcomer video alternative to GIF recently gaining momentum. Animated GIF images are restricted to 256 colors and are used in simple scenarios but are supported in all major web browsers.