This is so good. I love that you have picked a picture with some movement and emotion. It is so boring with all those standard portraits of people just standing there. I really love this one. The details in the mouth especially, because I know how hard it is to draw mouths.
not all..only some of them have been photographed..I always had hard time doing that..had to take several shots to get the perfect image..just make sure that the light source should be even from all sides..and avoid using flash