But, he added, "You can still make it casual. But this is just casual and poor quality. They didn't have to make a bad quality product to put that idea across."
Christopher Barr, a professional photographer in Arizona, agrees.
"It's obvious that a professional didn't take these. It hasn't been color-corrected. Even somebody with a modicum of Photoshop knowledge could improve these pictures immeasurably," he said.
"It's not a very good effort. It's a particularly poor effort given that he's taking pictures of such an important thing at such an important time."
But Lana Marks, a friend of the late Diana, Princess of Wales, told CNN's "AC360" show that she thinks William's mother would have been delighted by his approach.
"One of the things she told me is that she so much wanted William to have a normal life with his family in the future, with whoever he wed and had children with," she said.
"All of her dreams have come true and her legacy's coming true, and all the influences she's had on William, the normalcy, is showing through so greatly now. She would be immensely happy."