MIFF
Magick Image File Format (MIFF) is a raster image file format associated with the image processing software ImageMagick. It was originally named Machine Independent File Format.
It is designed to support all of the metadata and pixel formats supported internally by ImageMagick. For example, it supports floating-point samples and high dynamic range.
There is no formal MIFF specification. Each copy of the ImageMagick software includes a copy of the MIFF documentation, and each new version of ImageMagick may add new features to the format.
Despite the potential instability and ambiguity of the format, it is portable enough to be usable by other applications. But it is primarily useful for temporary files, and should probably be avoided for long term storage or public distribution.