There are 3 sites to recommend.
. You give them a picture of yours and then make it thinner. Pros: It is a free service. Cons: They do not deal with slimming in detail so sometimes the photos end up unrealistic.
. You make a virtual model inputing facial characteristics, height and body weight and the ones in your ideal weight and the outcome presented on you. Pros: It is free and if you have a lot of weight to lose it really shows the difference. Cons: Not all bodies are the same so they are never exact to your body and the fact that some areas are reduced more than others is not taken into consideration.
Ok this guy does everything. It takes your body and gives you the measurements you want with the face that you are supposed to have. Pros: This pictures are 90% accurate on what your face will look like in your goal weight. Cons: He charges for his work and the prices range from 8$ to 30$ depending on how much work he has to do.