Duchess Kate and Prince William have marked each of her children’s birthdays over the years with new portraits.The sweet tradition began when their eldest son, Prince George, celebrated his first year in July 2014. The little one walked in the photo taken by John Stillwell, looking all grown up in Petit Bateau denim overalls, a navy polo shirt and matching leather shoes.“He was very lively, very confident and very sure of himself,” Stillwell told Us Weekly of the toddler at the time.