The upper photo of the Curiosity Calibration Target was shot by the Mars Hand Lens Imager (MAHLI)on Mars.
The lower photo is a comparison shot done on Earth in artificial light.
Clearly visible is the influence the Mars atmosphere has on the perception of colors by the Bayer Pattern Filter CCD sensor used in MAHLI.
The colors in images from Mars can be adjusted (color and white-balanced) in a way that pictures taken there do appear as if taken under Earth lighting conditions. This makes it easier for scientists to recognize and identify geological features because of course no scientist is accustomed to see these under Mars lighting conditions.