In this VIS image, taken by the NASA - Mars Odyssey Orbiter on February, 26th, 2014, and during its 54.141st orbit around the Red Planet, we can see a small area of the North Polar Erg (---> Sea of Dunes). As the season changes from Spring to Summer, the Dunes surrounding the North Polar Cap, as you can see here, become darker and darker.
Only the round and bright Feature located on the right (Dx) margin of the frame (that we have already noticed in the past, when other pictures of this very same area were taken even by other Orbiters), seems to remain - basically - unchanged during the entire Martian Year. Unfortunately, we do not know what that Feature actually is, but our educated guess is that it could reasonably be a (relatively large) patch of Permanent Ice and Frost, thick and compacted enough to resist to the Winds' Action and then make it through the whole Martian Summer, when the temperature considerably raises, without sublimating or melting.
Latitude (centered): 79,7727° North
Longitude (centered): 198,7900° East
This image (which is an Original Mars Odyssey Orbiter b/w and Map-Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 18233) has been additionally processed, magnified to aid the visibility of the details, contrast enhanced, Gamma corrected and then colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Mars Odyssey Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.