So, in the long run, does it matter if a six- (or seven-) year-old child gives a Nazi salute? Does it matter that the six-year-old didn’t know what she was doing, that it was five or six years before Hitler even invaded Poland, and that the child grew up to inherit the British throne? Well, yes and no.

If the royal family were in any way ordinary, it would be straightforward to dismiss the whole thing in the way it should be – she was young, and in 1933-34 Hitler was still a funny man with a stupid moustache. But the royal family aren’t ordinary.

With Kate and George and Charlotte and morning sickness and party planning and Harry’s nightclub quest for true love, they’ve all worked incredibly hard over the past few years at positioning themselves as ordinary, lawn-mowing, car-washing, pizza-in-front-of-the-TV types – just like, well, almost like their actual subjects.

But the rebranding only works up to a point. It doesn’t matter how many times Prince William shares baby pics on Facebook or gets pictured in hunky search-and-rescue hi-vis while backdropped by equally alpha helicopters; he’s still not ordinary. None of them is ordinary. That’s the whole point. If they were, why have them in the first place? There’s only one British throne, and only one person gets to inherit it.

Besides, the thing about the royal family is that they, more than even the starriest, most intergalactic Hollywood celebrity, only really exist as an image. Collectively they are, by a very long margin indeed, the most photographed, filmed, written-about, Instagrammed, tweeted and featured people in the world. They don’t talk in public because they’re not allowed to (well, Prince Charles does, although it’s questionable whether anyone listens). So instead their existence is one long photo op, an everlasting Telegraph space-filler.

Princess Di understood this better than anyone. It was she who was credited with hauling the monarchy into – well, at least the 20th century, if not quite the 21st. She did it by understanding that what you did and how you looked in public was all that mattered, because that was where people could hand you a bouquet or claim boasting rights in the office afterwards because they’d once seen you get out of a car on the way to a tennis lesson. Her famous Panorama interview was a masterpiece of image manipulation. Ironically enough, so was her death.

Those who have spent time with any of the royal family usually say not only that they’re exceptionally well rehearsed and well researched, but that they’re exceptionally charismatic too. The Queen – 89 years old, 5ft 4in – holds a whole room every time she walks into it because she’s been the sole focus of that room or banquet or garden party for every one of the years that she has been monarch. She doesn’t have to do anything; she just has to be.

And the Queen also fully understands the consequences of image misjudgments. In the immediate aftermath of Diana’s death, the royal family got things very wrong and nearly paid the ultimate price. If the Queen hadn’t gone on national television to talk about her feelings, all the good work done over the past century – the Queen Mum and her fondness for horses, staying in London during the Blitz, what must feel like a thousand years of visitor-centre openings – could have been undone in the space of a couple of headlines.

So the royals are right to be snappish at Sun reminders that the erstwhile Saxe-Coburg-Gothas were ever anything other than as British as Windsor. The Queen wasn’t a Nazi any more than Churchill was. But for a family that isn’t allowed to talk, pictures end up telling far more than their share of the story.