Today's Image of Mars was taken by HiRISE shows the Phoenix lander almost two years after it landed on Mars. Only the backshell and lander are visible because the other parts, including the parachute, have been covered by dust. The lander's solar panels have collapsed, which makes it look unusual.
Scientists image the inactive Mars rovers to get a better idea about the Martian environment and how long it takes to cover different features. Unlike the Moon, which remains relatively static, Mars has heavy winds and sandstorms which are constantly altering the terrain. Footsteps on Mars would not last more than a few weeks on Mars.
Clicking on this image will take you to the original high resolution image from HiRISE. [See their caption]