Nice Hi-res photo. But where is the water? I see the trace of a wheel but it leaves trace not only in mud but in dust also I belive. Next time put an arrow and some explanation under the picture!
That waas an image from the Rover Opportunity. The water on the Martian surface is fleeting. The surface material is sandy and pooling is temporary. If you look below the track you will see a surface feature that has fluvial patterns. Water on Mars comes from below.
Quote: I have no idea how to draw arrows and such.
Open your pictures in Power Point or Photoshop or simply with Windows Paint, draw the arrows than save them as JPG and upload them to an image hoster. For example: www.imageshack.us