MNG stands for "Multiple-image Network Graphics" and may be pronounced "ming." It is based on the .PNG image format and supports animations.
The MNG format was designed to provide an alternative to animated .GIF files. It supports image transparency, JPEG data, and nested loops, which are not supported by the GIF format. Even though MNG offers better file compression and several other features not supported by GIF images, MNG is still not widely supported.