Nokia Picture Message
From Just Solve the File Format Problem
Nokia Picture Message (or Nokia Phone Picture Message, NPM) is a bi-level raster image format used by some Nokia phones. NPM images are 72×28 pixels, though the format supports other sizes up to 255×255.
Files begin with a header of at least 11 bytes. The header size depends on the size of a variable-length "text message" field.
Files begin with the ASCII string "