The dunes in this VIS image are located in Nili Patera, one of the two patera of Syrtis Major Planum.
Photo credit: NASA/JPL/Arizona State University
Note: If you click on the Nili Patera label, you'll notice that there are a number of photographs that are of the same landscape (more or less). Why would the THEMIS scientists keep taking pictures of the same ground over and over? I can think of three reasons off-hand: 1) doing so allows the scientists to monitor the ground for any fresh features, such as newly formed impact craters, 2) the scientists can monitor whether or not the wind is pushing the sand dunes along or not and, if so, how quickly the dunes are moving, and 3) because the photos are not exactly covering the same area, a larger mosaic of the area can be made at (more or less) the same resolution.