Kensington Palace released an altered photograph of Britain's Princess Catherine on Sunday, leading AFP and other news agencies to withdraw the image, the first to be officially released since her abdominal surgery.

The photo, issued to mark Mother's Day in Britain, shows the smiling Princess of Wales sitting on a garden chair, dressed in jeans, a sweater and a dark jacket, surrounded by her three laughing children, George, Charlotte and Louis.

But close examination shows that Princess Charlotte's left hand is misaligned with the sleeve of her cardigan, casting doubt on the authenticity of the image.

After publishing the photo provided by the palace, the Associated Press, Reuters and AFP decided to withdraw it.

"It has come to light that this handout photo... had been altered and therefore it was withdrawn from AFP systems," the agency said in a note to clients.

The AP said it had retracted the image because on "closer inspection, it appeared the source had manipulated the image in a way that did not meet AP's photo standards".

Kensington Palace did not immediately respond to AFP's request for comment.

The release of the photograph came after an unusually long public absence for Kate.

The 42-year-old princess, whose husband Prince William is heir to the British throne, has been recovering from surgery mainly at their home in Windsor, west of London, since leaving hospital on January 29.

"Thank you for your kind wishes and continued support over the last two months," read a message accompanying the palace's photo on the social media platform X.

"Wishing everyone a Happy Mother's Day," said the message, which was signed "C" for Catherine.

In a statement, the palace said the photo was taken "in Windsor earlier this week" by Prince William.

It was the first official image of Kate released by the royal family since her hospitalisation at the London Clinic on January 16 for an abdominal surgery.

- Conspiracy theories

The future queen was last photographed in public during a Christmas Day walk in Sandringham, eastern England.

Photos published by TMZ earlier in March showed Kate wearing sunglasses while being driven in a car, with the celebrity news site saying they were taken near Windsor Castle.

UK media outlets including the Daily Mail and The Sun chose not to publish the pictures.

The sighting came after a flurry of conspiracy theories on social media over the famously hard-working and dutiful princess's absence from the spotlight.

The speculation came despite Kensington Palace clearly saying at the time of her surgery that she would be "unlikely to return to public duties until after Easter".

It also said the surgery was not related to cancer.

Kate's hospitalisation came almost simultaneously with the announcement that William's father, King Charles, had been admitted for surgery for a benign prostate condition and subsequently diagnosed with an unrelated cancer.

Charles, 75, visited his daughter-in-law's bedside after being admitted himself on January 26.

The king withdrew from public duties during his treatment, though he attended church services and held his weekly audience with the prime minister.

- Camilla steps in -

Charles's wife Queen Camilla, 76, has been the most visible senior royal, stepping in to cover many of her husband's public duties during his treatment.

She is now on a break until March 11, when she is expected to join William and other senior royals at the annual Commonwealth Day service at Westminster Abbey.

She is reported to be on holiday this week, effectively meaning all four of the most senior royals are out of action.

The princess is one of the most popular members of the royal family.

She and William have taken on more royal duties since his younger brother Prince Harry and his wife Meghan left for the United States in 2020, and the king's brother Prince Andrew stepped back because of his friendship with the convicted sex offender Jeffrey Epstein.