The Chocolate Doom icon is based on an image by Chris Metcalf
(http://www.chrismetcalf.org/) which is copyrighted to him:

    http://www.flickr.com/photos/laffy4k/448920776/

The "foo8.ico" files are 8-bit depth only, while the "foo.ico" files
contain full 32-bit versions, scaled to different sizes and with proper
alpha masks (as well as the 8-bit versions).  The 8-bit versions are
used when setting the icon within SDL, as SDL under Windows displays
full color icons in a very poor quality.  The full-color versions are
used in the resource files.