Looks OK to me - maybe you have your color settings low.
Try this:
If you're on a Windows machine, right click on a open area of the desktop and then Properties > Settings (tab at the top). Make sure the Color Quality setting reads "Highest (32 bit)." Sometimes if you're in 16 bit or lower, it can make photos and other graphics look weird. If you're using a Mac, I think it's in the System Preferences > Display menu.
Hope that helps.