On Saturday, Prince William and Princess Kate celebrated the birthday of their oldest son, Prince George, with a “special and not showy” party in Windsor, but for the public, they continued the tradition of releasing a birthday photograph of their oldest son. On Saturday, their Instagram account shared a picture of George posing in a blue and white oxford shirt on a set of steps in Windsor.

William and Kate have been releasing annual photos of their children George, Princess Charlotte, and Prince Louis, for most of their lives, and the annual tradition has allowed the family to balance a sense of normalcy and privacy for their kids with the public’s desire to see the next generation of Windsors. 

In some years, avid photographer Kate took the photos of her young children, but this year all three images were taken by Millie Pilkington, a Dorset-based portrait photographer. She also took a family photo that the couple released on Father’s Day. “A heartfelt thank you to @princeandprincessofwales for entrusting me to take his portrait,” Pilkington said on her Instagram account. “As always, feeling deeply honored and very lucky. And wishing Prince George the very happiest of birthdays."

Pilkington has a long history with the royal family. In April 2011, she served as the private photographer for William and Kate’s wedding reception. Afterward, she told The Observer that the atmosphere was “absolutely extraordinary” and added that the newlyweds were “buzzing with happiness.” In 2014, she took a family portrait of Prince Edward, his wife Sophie, and their two children, Louise and James, to celebrate the prince’s 50th birthday.

Over the last year, George and his siblings have been attending more public events and stepping into their royal roles. In May, he made history as the first likely future king to serve in a coronation ceremony when he was a pageboy for his grandfather, King Charles III. So far this summer, he joined his family on the balcony for the king’s first Trooping the Colour parade, attended a cricket game and a match at Wimbledon, and visited an air show. 

Earlier this month, a palace insider told People that William and Kate’s kids have been raised in a stable environment. “Those children look pretty happy with life,” the insider said. “A lot of it is the stabilizing normality Kate brings—and that’s how she grew up. William absolutely loves it. Long may it continue. They are the future of the monarchy.”