Interesting shot. Not sure how big you are as that child's dad, but I can tell you this: Your son has proportionally large hands to the size of his head. My oldest son did as well. He's 21 now and a college junior. He's 6' 5" 260 and wears size 17 shoes. His hands are the size of large pie plates to this day. Could palm a basketball in 7th grade.
Make a note of this and don't forget. Measure your child's height at age 2. Good rule of thumb is that his height in inches at 2 years is 1/2 his expected adult height. My son was 39" tall at 2 and is between 6' 5" and 6." Pretty much spot on for both my boys at 2 years of age.
The large hands are a dead giveaway that he's going to be a big kid!
dave