This image from NASA 2001 Mars Odyssey spacecraft was collected at the same time as yesterday IR image. The dunes are dark in the VIS image, because the material is darker in color than the surrounding material. Latitude: -54.3016 Longitude: 13.1403 Instrument: VIS Captured: 2015-01-21 17:09 http://photojournal.jpl.nasa.gov/catalog/PIA19229