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, row-aligned |
  +--------+-----------------------------------------------------------+