This image has been composed so Obama is in the center of the image with you looking slightly up towards him, making him the main focus of the image with a very high power look, but yet approachable with how he is sitting. I feel the lighting in this is a bit harsh and would have suited it better with a slighter softer lighting.
Only when you stand in just the right location do the portraits of Michael Murphy pop into view. His highly detailed works are created using a large array of media, using multiple layers that only align from one viewpoint. The resulting images are so seamless, they almost seem to be created with Photoshop. See more of his work at mmike.com.