Yesterday, Alexis Madrigal examined the process of white-balancing photos. The process makes photos from Mars appear as if they were shot under Earth-sunlight, allowing geologists to apply their decades of intuition about, well, how rocks should look to photos from Mars.
From NASA's Astronomy Picture of the Day, here's another pair of white-balanced photos. First, the wall of the Gale Crater, some distance from the Curisoity Rover, in Martian light:

And here, as if it was in Earth sunlight:

Images: NASA
Below, recent Pictures of the Day:
This article available online at:
http://www.theatlantic.com/technology/archive/2012/08/picture-of-the-day-the-gale-crater-from-mars-to-earth/261168/