Prince William and Kate Middleton
Sarah Burton gained global praise when the Duchess of Cambridge wore Burton’s Royal Wedding dress creation. Reuters

English celebrity magazine Grazia admitted to altering a cover photo of Kate Middleton to make her skinnier. The May 9 special Royal Wedding issue featured a doctored picture of the duchess in her Alexander McQueen wedding gown, in which Middleton appeared to have an extremely narrow waist.

The magazine apologized for the accident, which had already sparked a debate over Grazia's practices, according to The Guardian.

"We would like to reassure all our readers that we did not purposely make any alternations to the Duchess of Cambridge's image to make her appear slimmer, and we are sorry if this process gave that impression," Grazia commented.

Grazia originally took an image of Middleton holding hands with her husband, Prince William, after they exchanged vows. They then adjusted the photo to remove the Duke of Cambridge. In doing so, the magazine cut off Middleton's right arm, attaching instead a mirror image of her left arm so that she appeared alone. During that process, Middleton's waist was cinched.

The incident was the latest in the on-going debate about the portrayal of women in society.

Last week, the L'Oreal makeup company was forced to remove two advertisements from magazines after it was revealed that the photo images had been altered. The two ads -- both for "anti-aging" foundations -- featuring actress Julia Roberts and supermodel Christy Turlington were deemed misleading.

"Pictures of flawless skin and super-slim bodies are all around, but they don't reflect reality," Liberal Democrat parliamentarian Jo Swinson told CNN. "With one in four people feeling depressed about their body, it's time to consider how these idealised images are distorting our idea of beauty.

"Excessive airbrushing and digital manipulation techniques have become the norm, but both Christy Turlington and Julia Roberts are naturally beautiful women who don't need retouching to look great."