FARBFELD IMAGE FORMAT SPECIFICATION

  +--------+-------------------------------------------------------+
  | Bytes  | Description                                           |
  +--------+-------------------------------------------------------+
  | 8      | "farbfeld" magic value                                |
  +--------+-------------------------------------------------------+
  | 4      | 32-Bit BE unsigned integer (width)                    |
  +--------+-------------------------------------------------------+
  | 4      | 32-Bit BE unsigned integer (height)                   |
  +--------+-------------------------------------------------------+
  | [2222] | 4*16-Bit BE unsigned integers [RGBA] / pixel          |
  |        | pixels in rows, ProPhoto RGB, not alpha-premultiplied |
  +--------+-------------------------------------------------------+