This image was acquired in Ius Chasma, a major section of the western portion of the giant Valles Marineris trough.
We see a portion of a steep slope with gullies extending downhill (towards bottom of image). Many of the gully floors are dark, and in some places that dark material extends onto the fan-shaped deposits of the gullies. These dark features are candidates for recurring slope lineae (RSL), which are seasonal features that grow incrementally. The relation between RSL and gullies is not clear: does the RSL activity carve the gullies, or do they simply follow the gully topography created by other processes? [More at link]