The growing mystery surrounding the whereabouts of Kate Middleton deepened on Sunday as a photo shared by Kensington Palace was pulled by four major news agencies over fears the image was “manipulated.”

On Sunday, to coincide with Mother’s Day in the U.K., the official Prince and Princess of Wales Instagram account shared a picture of the princess with her three children, Prince George, 10, Princess Charlotte, 9, and Prince Louis, 5. The picture is not dated.

“Thank you for your kind wishes and continued support over the last two months,” the caption to the picture reads. “Wishing everyone a Happy Mother’s Day. C.”

Within minutes of the photo being posted, social media was ablaze with accounts purporting to be professional photographers suggesting that the image had been manipulated, pointing to certain elements of the photo. In particular, people pointed to the sleeve of Princess Charlotte’s arm not lining up and the lack of focus on Prince George’s right hand, both suggesting photo manipulation.

Later on Sunday, the BBC reported that the four big photo agencies — Getty Images, Reuters, AFP and AP — ordered “photo kill” notices over the image over the manipulation concerns.

Although PA Media, the UK’s biggest news agency, through which the Royal Family regularly releases its official information, has said it had not killed the picture on its service.

The whereabouts of the Princess of Wales has become the subject of, often wild, speculation in recent weeks after the royal underwent a planned abdominal surgery at The London Clinic on Jan. 16. After the surgery, Kensington Palace revealed that the procedure was a success and that the princess would remain in the hospital to recover for 13 days. The palace also said the princess would be stepping back from public duties while she recovered.

Despite official statements, speculation and conspiracy theories have abounded, suggesting that the princess was in poorer health than the palace was willing to admit. The rumor mill went into overdrive after Prince William pulled out of a memorial service due to a “personal matter” at the end of February.

It was hoped the picture posted on Sunday would quell some of the more scurrilous rumors about the princess, but the use of a supposedly manipulated image has only served to add to the mystery.