The ESA's Mars Express website provides the image (pictured on the right) of water ice found in a Mars crater near the Martian north pole. The photograph was taken by the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express spacecraft
The HRSC obtained these images during orbit 1343 with a ground resolution of approximately 15 metres per pixel. The unnamed impact crater is located on Vastitas Borealis, a broad plain that covers much of Mars's far northern latitudes, at approximately 70.5º North and 103º East.
The crater is 35 kilometres wide and has a maximum depth of approximately 2 kilometres beneath the crater rim. The circular patch of bright material located at the centre of the crater is residual water ice.
You can read more about the discovery here on the ESA website.
The ESA's Mars Express 
