Starting in Kindergarten, put the child's graduation year on a large tshirt. Take a picture each year with same shirt to watch the child grow into the shirt. Display at graduation party! **Take the picture on the last day of school.
My parents never took enough pictures of us! Another great idea: Take a picture of the first and last day of school to see how much they change over the year - this would make a really cute photo book when they graduate high school.