Quake 2 Texture
Quake 2 Texture (.wal), or Quake Texture, is a raster graphics texture format associated with Quake 2, and related video games.
Although references to the format, and sample files, are easily found on the web, we have not identified any technical information about it.
It evidently contains multiple copies of the same image at different sizes. The dimensions of the primary image appear at offset 32.