Yes, you have to send pictures in whenever you do any registry work with AMHR. Look on their website to see what they require (4) and what they want and don't want to see in each pose.
You need a photo of each side of the horse that shows all four legs. you need a photo of the back of the horse and a photo of the horse from the front. The front shot should have the forelocks moved to the side to show any markings. If there are markings under the mane, you might want to send a 5th photo with the mane moved to show those markings.