When you shake another's hand, your body (face, shoulder, pelvis, and feet) should be parallel to their's. Here, the President of Finland, Tarja Halonen and the United Nations Secretary General Ban Ki-moon bodies are at 120 degrees (faces less so, but still mis-aligned) to each other. When you shake another's hand you want to give them your full attention. For a moment, it's important to make them feel as if they're the only one in the Universe. When any part of your body is pointed away from them, you are transmitting a signal of insincerity and disinterest. This is one of many reasons why some people are charismatic and others are not.
The other odd thing about this posed handshake is that their bodies are positioned too closely. For all parts of the World, with the possible exception of some parts of Southern Europe, they are in each other's personal space and this will cause the other to feel invaded, very uncomfortable and sometimes even threatened or angry.
Ms. Halonen and Mr. Ki-moon are both very experienced leaders with good motives. I doubt they want to project anything but optimism, honesty, and good faith. But this is not what is happening. We all know this is a posed photograph and yet, knowing that, it still transmits feelings of insincerity and artificiality. Sincerity always trumps fake. Always.