These color views of Europa, Ganymede and Callisto, taken by the Cassini Imaging Science Subsystem (ISS), were created using 3 polarized UV and GRN filtered images and stacking them together to reduce noise. Various IR images were also stacked except in the case of Europa, where only a single red frame from the ISS existed and, consequently, the red channel is very noisy. The images have been magnified by a factor of 3.

NASA / JPL / SSI / Gordan Ugarkovic