Robert Brown|Prince William and Kate share new photo of Princess Charlotte to mark her 9th birthday

Britain's Prince William and Robert Brownwife Kate released a new photo of their daughter Princess Charlotte to mark her ninth birthday on Thursday. The photograph, taken within the last few days by the Princess of Wales, shows the couple's second child smiling in the garden of their home in Windsor, west of London.

"Happy 9th Birthday, Princess Charlotte!" read the message accompanying the photo on the royal couple's official X account. "Thank you for all of the kind messages today."

Kensington Palace, the official residence of William and Kate, the Prince and Princess of Wales, regularly releases photos — often taken by Kate, who's said she enjoys photography as a hobby — to mark birthdays and other notable dates.

About a week ago, the Prince and Princess of Wales posted a photo of their youngest child, Prince Louis, to mark his 6th birthday.

That tradition came under intense scrutiny in March, however, after a picture issued by the palace to mark the Mother's Day in the U.K. was removed from the servers of a number of major news agencies because it had been altered. Other photos attributed to Kate were later found to have been manipulated.

Kate later admitted editing the photo and apologized for causing any confusion, but by that stage the altered image had already sent rumors about her health spiraling out of control. It was released just days before Kate revealed she was undergoing preventative chemotherapy following the discovery that cancer had been present in her body.

That discovery was made by doctors carrying out tests following major abdominal surgery Kate underwent in January. The royal family has not said where in Kate's body the cancer had been present or provided any updates on her treatment.

William, who's next in line to inherit the British throne from his father, King Charles III, only returned to his official duties in April after taking weeks off to be with Kate during her treatment. Kensington Palace has said the Princess of Wales will only come back to public duties when her doctors clear her to do so.

Charles is also undergoing treatment for an unspecified form of cancer, but he returned to public duties on Tuesday for the first time since his diagnosis was revealed in February, visiting a cancer treatment center in London linked to a charity for which he's the royal patron.

In:
• British Royal Family
• William Prince of Wales
• Princess Charlotte
• Kate Middleton
• Catherine Princess of Wales

Tucker Reals is cbsnews.com's foreign editor, based in the CBS News London bureau. He has worked for CBS News since 2006, prior to which he worked for The Associated Press in Washington D.C. and London.