The reason I chose this picture was because of the expression on the man's face. At first I wasn't sure if he was jumping on the horse or falling off. He is in definite limbo and from his body movements it's hard to tell. But this is the final thing that I thought about. There were many other steps that led me to this final question.
The photographer used a direct approach to capture the scene and makes it seem as if the man and horse are about to come out of the photograph itself and become real. They are close to the camera and are the main source of focus and light in the photo. The use of color and shapes become one, guiding our eye, and giving us a sense for the picture.
What starts our eye is the downward angle of the horse's back. Then, in stark contrast, is a white saddle strap hanging down the neck in a half circle. This leads us to a man whose arms and leg complete the circle. From there we go inside the circle and find another half-circle made by the bridle fabric. This leads us up the horse's face and across, following the color. We then hit the man's face and find our subject.
Is this a man bracing for impact? Is he giving out a whoop while he jumps on the horse? He looks excited and is looking forward. A man that is about to fall off a horse might have a similar expression, part grimace, part thrill rush, but he would be looking down in anticipation or looking at the horse like he was betrayed. But this man is looking forward and has no fear about jumping on. He is expecting a smooth jump and is looking forward to see what comes next.
The more I examine this photograph the clearer the photographer's intention seems. First off, was to capture the sense of motion in the photo. To express to the viewer that this is a landscape in motion and the people are like Indians, always moving, part of the horse and shaped by the region. The man and the horse are one. The circles revolve around them and connect them together. The tufts of hair above each make them seem the same species and blends them into one whole.
If you look at the background, you see more shapes in motion. The black shapes look like horses and the white shapes I just assumed were other men, because that symmetry was already provided. Given the easiness of the man's jump we can picture a similar scene with the others. Ten other men jumping on horses right behind this one, all charging at us, stampeding off to a distant plateau.