We have enhanced colors to be corresponded with colors used by NASA:

http://www.nasa.gov/mission_pages/msl/multimedia/pia16105.html

The images for panorama obtained by the rover's 34-millimeter Mast Camera. The mosaic, which stretches about 30,000 pixels width, includes 140 images taken on Sol 3 (August 8, 2012).

Curiosity rover added from of the earlier B&W photos.

Other panoramas of Mars by Curiosity rover: