The first photo is about simplicity. Your eye focuses on the boat and nothing else in the picture takes away from the quality. It is a good example of of simplicity and it was posted in .jpeg format.
The second photo is an example of framing. It shows a natural way of using mountains to frame the water and mountains in the distance. This photo was posted in .jpeg format.
The third image is an example of leading lines. The lines are the main component of the photo and what catch your eye. This photo was posted in .jpeg format.