The Princess of Wales, sitting beside the forest of ferns decorating the endless banqueting table at Windsor, looks cheerful and means to convey that by her smile. Beside her, President Donald Trump has put on his happy face and made eye contact.
Before the smiles, Trump had assumed his determined look, which I’m afraid can make him resemble a toad. It would have been no surprise if a thin sticky tongue had darted out and captured a fly on a nearby floral display. When nodding at the truths of the King’s remarks, though, he assumed the demeanour of the Japanese waving cat, the maneki-neko.
“I want to know what she’s thinking,” remarked one woman on Facebook. Others wondered what he’d said to her. For, though it’s a great photo, the context is all.
I think the exchange of glances took place during the King’s speech, just at the moment when he had said that, if things had been different: “I myself might have been married off within the Nixon family!” That thought certainly invited a shared smile.
But imagine how we shall think of this picture in future years. It will depend on what becomes of the two of them. Trump is a little unsteady on his feet. He held Melania’s hand as they walked from the helicopter, even though she had her work cut out walking over grass in high heels.
Perhaps, like his holding of Theresa May’s hand in the early days of his first presidential term, it was for support rather than as an expression of affection.

President Trump and former prime minister Theresa May briefly joined hands as they walked along the White House Colonnade – Christopher Furlong/Getty Images
Suppose on returning home he tumbles down the steps of Air Force One, never to rise again. Well, it would make his last smile with the Princess all the more special.
Intimations of mortality make famous photos all the more powerful. What could compare with the picture of the last Queen, in widow’s black, down to the coronavirus mask, sitting alone in a sea of medieval woodwork at St George’s Chapel, Windsor, during the funeral of her husband of 73 years?

Queen Elizabeth II watches as pallbearers carry the coffin of her husband, Prince Philip, Duke Of Edinburgh, into St George’s Chapel – Yui Mok/WPA Pool
Or think of Diana, Princess of Wales, pictured in 1992, sitting on a stone bench in front of the Taj Mahal. Nothing could have been more romantic – except that no one was sitting beside her. She was divorced four years later and dead through a terrible accident another year on.

Diana, Princess of Wales, sits in front of the Taj Mahal during a Royal tour of India – Martin Keene/PA
Perhaps it’s just me, but funerals do seem to make for more memorable images than weddings. It may be because they are definite and final, whereas weddings are the beginning of an undefined lifetime.
Remember the black and white photograph of three queens in 1952 – Queen Mary, the widow of George V, Queen Elizabeth, the widow of George VI, and Queen Elizabeth the new young queen – standing together veiled in black. There, the funeral of the King her father was the beginning of the late Queen’s long and happy reign, we know now, adding poignancy to the scene of sadness.

Queen Elizabeth, the Queen Mother (right), in mourning with Queen Elizabeth II (left) and Queen Mary (centre) at the funeral of King George VI – Mirrorpix
So, even there, it is more than the photograph itself that makes the image powerful.
An extreme example of the need for a caption is a celebrated albumen print by Roger Fenton from 1855. In a bare scoop of land that could be the surface of Mars, lie stones and among them round lumps – cannonballs. The title is “The Valley of the Shadow of Death” and the making of the image was Tennyson’s poem “The Charge of the Light Brigade”.

The Valley of the Shadow of Death is an albumen print photograph by Roger Fenton, taken in 1855 during the Crimean War – SSPL/Getty Images
I very much hope that the shared smile of Trump and the Princess of Wales will be remembered with happiness.
But that depends on what happens next, and whether we can look back and laugh.