This photo of Kate, Princess of Wales, with her children was published by Kensington Palace on March 10 in celebration of Mother's Day in the United Kingdom.

News agencies say she has been manipulated.

(Credit: Kensington Palace)

(CNN) --

Kate, Princess of Wales, took responsibility and apologized for an edited official photograph that several international news agencies removed over concerns it had been manipulated.

Kate said she was sorry for "any confusion" caused by the image, having "experimented" with photo editing.

The photograph, released on Sunday to mark Mother's Day in the United Kingdom, was the first official image of Kate since she underwent abdominal surgery in January.

However, hours after Kensington Palace published it, four major photography agencies warned against its use, expressing concern that it had been edited.

Kate wrote on

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The family traditionally releases a photo on Mother's Day, but this year's image came amid a backdrop of intrigue and confusion over Kate's prolonged absence from the public scene.

Kensington Palace said the photograph was taken by William, Prince of Wales.

It appeared on the front pages of several British newspapers and websites before any doubts were raised about it.

Kate