Today's Image of Mars comes from HiRISE and shows layers of water deposited sediment near the western rim of a large ancient crater. The layers seen below have a morphology similar to that seen elsewhere on Mars where channels have emerged into craters, creating alluvial fans.
In this case scientists cannot find obvious signs of a channel, but believe that the deposits left behind have been erased by wind erosion and other factors.
Clicking on this image will take you to the original high resolution image from HiRISE. [See their caption for the image]