You can do a nice comparison shot in Jasc (now Corel) Paint Shop Pro. They even allow you do download the full trial version and use it for 30 days. You can also do layers with it -- take one picture as the bottom layer (like a beginning shot) and then put another picture on top of that layer (50% see-through) to see how much your growth has changed. If you need help I wouldn't mind helping or doing it for you.