From http://www.jpl.nasa.gov/galileo/

   
             Global View of Io (Natural and False/Enhanced Color)
                                       
   
   
   NOTE: This JPEG image is made available in order to share with the
   public the excitement of new discoveries being made via the NASA/JPL
   Galileo spacecraft. Galileo scientists are in the process of
   calibrating and validating this data. The full digital image necessary
   for scientific analysis will be released within one year of receipt of
   this orbit's last data.
   
   This image is available only on the WWW; it is not available in
   hardcopy or other forms.
   
   
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Global View of Io (Natural and False/Enhanced Color)

   
   
   Global view of Jupiter's volcanic moon Io obtained on 7 September,
   1996 Universal Time using the near-infrared, green, and violet filters
   of the Solid State Imaging system aboard NASA/JPL's Galileo
   spacecraft. The top disk is intended to show the satellite in natural
   color, similar to what the human eye would see (but colors will vary
   with display devices), while the bottom disk shows enhanced color to
   highlight surface details. The reddest and blackest areas are closely
   associated with active volcanic regions and recent surface deposits.
   Io was imaged here against the clouds of Jupiter. North is to the top
   of the frames. The finest details that can discerned in these frames
   are about 4.9 km across.
   
   Launched in October 1989, Galileo entered orbit around Jupiter on
   December 7, 1995. The spacecraft's mission is to conduct detailed
   studies of the giant planet, its largest moons and the Jovian magnetic
   environment. The Jet Propulsion Laboratory, Pasadena, CA manages the
   mission for NASA's Office of Space Science, Washington, DC.
   
   This image and other images and data received from Galileo are posted
   on the World Wide Web, on the Galileo mission home page at URL
   http://www.jpl.nasa.gov/galileo.