This is an image of a string of the Bahama islands in the Caribbean taken by an unnamed astronaut who was a part of the Expedition 44 crew aboard the International Space Station. Canals of water that have cut between the islands showing the destructive power of water. The darker blue streaks are the deeper parts of these canals, and the lighter blue areas are shallow regions. The flow of water is driven by the daily tidal changes. Artistically, this photo blends together light blue and white naturally. Also, the white puffy clouds and their darker shadows are a nice addition by adding more contrast to the image.
This imaged is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center
Link to original image: https://visibleearth.nasa.gov/view.php?id=86651