The Mars Orbiter Camera's blue wide-angle instrument on Mars Global Surveyor took image S23/00831 as part of MOC's routine observations of Mars for weather monitoring purposes. It was garbled upon reception on Earth because Mars Global Surveyor was close to solar conjunction at the time. Little did MOC's operators know that this would be their instrument's last image ever sent from Mars.
As garbled as it looks, there is a tiny bit of "sense" in the image, a small area of cratered terrain near the top. Ken Edgett says this is in southern Terra Sirenum near the Copernicus basin.