PM (XV image)
From Just Solve the File Format Problem
PM is a raster image file format.
It is supported by the XV graphics software. According to XV's documentation, "this format was developed at Penn, and is rarely seen outside of Penn."
To be clear, this is not XV's native image format. But we need a name for it, and the name PM is also used by several other formats.
Identification
Files begin with a signature consisting of ASCII characters "VIEW
" or "WEIV
".