The Princess later apologised for digitally manipulating the family picture, taken by Prince William in Windsor, explaining that “like many amateur photographers, I do occasionally experiment with editing”.
Now, a section specifically dedicated to retouching forms part of the Royal Collection Trust’s new exhibition entitled Royal Portraits: A Century of Photography.
Using historical examples of retouched pictures of the royals, the exhibition explores the theme in select photographs and letters on display in The King’s Gallery.
Alessandro Nasini, the exhibition’s curator, explained that the process of retouching is a “very important part of the royal portraiture”.
Speaking at the press viewing, he told The Telegraph: “The retouching has been around since photography was invented, but because portraiture is a creative process, retouching is very much part of it as one of the tools that the photographer has to use as a way of translating the vision they had in their mind.
“Retouching could be as simple as cropping an image to making a composite image by using different photographs to create one final single image.”
The section includes a letter from photographer and husband of Princess Margaret, Lord Snowdon, stating that “something will have to be done about the halo of leaves round the top of Prince Philip’s head” in a picture he took of the late Queen’s young family.
The two photographs, one without the leaves and one with them circled with an annotation of “take out”, are put on display beside the letter.
In a label explaining the “stages of a typical royal portrait commission”, retouching is listed as number four of six stages.
It reads: “While some photographers prefer to retouch before providing the first proofs, others only do so on the selected portraits. Retouching may also be requested by the sitter.”
In another section of the exhibition, a label of Annie Leibovitz’s 2007 portrait of the late Queen explains how the photographer superimposed her figure onto a background.
“Using digital post-production, Leibovitz has superimposed the figure onto a digitally enhanced photograph of the Buckingham Palace gardens,” it states.
The exhibition, which opens to the public on Friday, includes portraits of the family taken by renowned royal photographer Cecil Beaton, as well as Dorothy Wilding, Leibovitz and David Bailey among others.
It also contains a previously unseen photograph of four royal women, including Queen Elizabeth, Princess Margaret and their newborns, on display for the first time.
The intimate picture of royal motherhood was taken by Lord Snowdon as a token of thanks to Sir John Peel, the royal obstetrician who delivered four royal babies within two months. A letter written by Princess Margaret addressed to “Darling Lilibet” is displayed next to the picture in which she suggests that her sister sign the portrait for the doctor.
It reads: “Here are the photographs – minus moles and spots of white – which Tony sends with his love…Would you like to sign it and then I will catch Kate to do the same and send it to him as a souvenir of an extraordinary two months of delivery.”
Taken at Kensington Palace, the picture shows Princess Alexandra holding James Ogilvy, the late Queen holding Prince Edward, Princess Margaret holding Lady Sarah Chatto and the Duchess of Kent holding Lady Helen Windsor.
Among the other highlights of the new exhibition are the Queen Mother’s personal copy of her daughter’s Coronation portrait and the earliest surviving colour photographic print of a member of the royal family.
The exhibition includes more than 150 items from the RCT and Royal Archives.
Nasini, the curator, said: “The Royal Collection holds some of the most enduring photographs ever taken of the royal family, captured by the most celebrated portrait photographers of the past 100 years – from Dorothy Wilding and Cecil Beaton to Annie Leibovitz, David Bailey, and Rankin.
“Alongside these beautiful vintage prints, which cannot be on permanent display for conservation reasons, we are excited to share archival correspondence and never-before-seen proofs that will give visitors a behind-the-scenes insight into the process of creating such unforgettable royal portraits.”
The selection of the images is an independent process by the curator but the Telegraph understands the King was made aware of it.
As former chairman of the RCT and now patron, the monarch “is very much interested in what we do, including what we present in the King’s Gallery”, Nasini added.
The exhibition runs from May 17 to October 6 in the King’s Gallery.