In the last image taken of Io by New Horizons' Multispectral Visual Imaging Camera (MVIC), on March 3, 2007 at 06:06 UTC, the plumes of Tvashtar and Prometheus are lit brightly by the Sun, lying nearly behind the moon. Also visible in the image is the much darker crescent of Callisto. Callisto orbits at more than four times the distance of Jupiter than Io does.

NASA / JHUAPL / SwRI