Below I have posted some global mosaics of Callisto, the Jupiter's second largest moon.  In all cases, missing data is filled in by lower resolution images or by reprojecting other images to fill the gaps. In the final image the color is entirely derived from other data.  All images are from NASA's Galileo spacecraft. The color variations between images are due to the fact that they are made using differing color filter combination. 

 

 

 

Processed images Copyright Ted Stryk, Raw Data Courtesy NASA/JPL