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. View of Callisto from Voyager and Galileo View of Callisto , most distant of the four large moons of Jupiter.
North is to the top of the picture.
This could be dark ejecta from a small impact crater. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment.