Wow!. This is just the beginning of what we can expect from the Mars Reconnaissance Orbiter.
I've been studying these gullies that occur in Mars' souther hemisphere craters for several years -- mostly in photos taken by Mike Malin's camera, the MOC, onboard Mars Global Surveyor.)
The Mars Orbital Camera is no slouch, with narrow angle capabilities for as high as 1.5 meters per pixel. It's sent us nearly a quarter of a million photos since its arrival in 1997 (and it's still operating well after more than 9 years in orbit,) but the narrow angle photos are grayscale and not quite as detailed as what we can get from MRO's HiRISE camera which does sub-meter resolution and in color.
Good times!
