How do they do that?

 Images like this are called composite images. They are two images combined to make one. The comfort and safety of your tiny baby is my number one priority throughout the shoot. I would never put your baby into dangerous or uncomfortable positions for a photograph. I am aware that there are lots of 'positions' and props that are questionable when it comes to safety, I don't take any risks. To produce images like this your baby is initially photographed on the safety of a newborn posing beanbag, then that image is blended onto a 'digital prop' to achieve these results.