Take the photo with the camera placed on a tripod or table that wont change the height. Then, sit all the way back in a stiff chair (wood or one that doesnt recline) so that your head is the same height in each shot. Do this for a side, front and rear shot. The rear shot is optional, but it's always better to have something and not need it than to need something and not have it.

Can you post your side photo so that we may compare them?