Unisys has a patent on the LZW compressor used in gif images.  Use of giflib
is highly discouraged as it may put you into legal difficulties with UniSys.
I take no responsibility for any liability you may incur by using this
software.  If you must access gif files, use libungif (available from
sunsite.unc.edu/pub/Linux/libs/graphics/), which writes uncompressed gifs
rather than gifs utilizing LZW compression.

Eric Raymond, the previous maintainer of giflib has this to say:
   Note: due to Unisys's increasingly aggressive interpretation of its
   patent claims on the LZW compression format, I can no longer recommend
   the use of the GIFLIB library or utilities.  GIFLIB may be withdrawn
   in the near future.
   
   For extended discussion of the situation, see 
   http://www.cloanto.com/users/mcb/19950127giflzw.html, The GIF
   Controversy: A Software Developer's Perspective. Essentially,
   since 1996 Unisys no longer exempts even `freeware' from its
   licensing requirements.  If you use this library in any way and Unisys
   decides it doesn't like you, you could be open to lawsuit.

