I have trained Teddy to sit, lay down and stay and he does this beautifully with the camera (there are some examples in my albums). His behavior is reinforced with treats and praise, of course! He was also taught SEE ME which I use with a click of my fingers. In this way, he will focus on my hand and the click so I can position his eyes and face in the desired photo angle.
It's worked a 'treat'! Took a few months of practice, but worth it in the end, since I now have a POSER for a puppy