They're a remembrance of a time long since forgotten. They're a brief moment in history captured in perpetuity for future generations. They're a glorious celebration of humanity's inherent kindness. They're a painful reminder of the incomprehensible and intolerable cruelty of mankind. They're a recollection of society's greatest triumphs and its failures.
Almost more than any of these though, they're an hour of such unfathomable tediousness, reliving every excruciating holiday excursion ever taken by a friend, relative, work colleague or next door neighbour. "This is Sheila in front of the Great Pyramid of Giza". "This is Sheila in front of the Taj Mahal". "This is Sheila in front of the Eiffel Tower."
Happy, sad, uplifting, soul-destroying or plain banal - "This is Sheila in front of the Sydney Opera House" - they have come a long way from the early 19th century when merely a handful were taken to the present day when they are snapped in their millions on a daily basis.
From high end fashion and war-torn reportage to paparazzi and humble selfies, photography is everywhere. It captures, influences and documents the world we live in like never before. For better or worse - in the majority of cases, much worse ("Hell fire, exactly how many more monuments do we need to see Sheila standing in front of?") - we're all photographers now. Smartphones have made sure of that. And while conventional media may not quite be awash with our efforts, social media most definitely is.
This wasn't always the case. Think of the most iconic images of the last 100 years and a few immediately spring into our visual mind. They include the Napalm scarred girl running from her Vietnamese village, Mandela walking free, the man standing in front of the tanks in Tiananmen Square, the raising of the US flag on Iwo Jima and Einstein sticking his tongue out.
Not surprisingly, a number of them feature the dynastic Kennedys- Jackie, still wearing her blood splattered pink Chanel suit as she stands next to Lyndon B. Johnson as he's sworn in as the next President aboard Air Force One and JFK junior saluting the coffin of his dead father.
In the future, famous images are just as likely to come from enthusiastic and talented amateurs as they are from seasoned professionals, which explains the inclusion of both among the contestants on Master of Photography (Thursdays at 8pm or via catch up) on satellite's premier cultural station.
Following on from Portrait Artist of the Year and Landscape Artist of the Year, Sky Arts has wisely eschewed Wax Fruit Artist of the Year and Dogs in Human Situations Artist of the Year and instead plumped for this new search for a star snapper.
Airing over eight weeks, the aspiring Avedon's, budding Bailey's and emerging Erwitt's from across Europe are fighting for a prize of €150,000, plus a gallery show of their own.
They are judged by a permanent panel of three experts, one of whom, Simon Frederick, seems to have the same look, not to mention, artistic temperament as Mugatu from the Zoolander films. Thank heavens then for Oliviero Toscani, who gave us the controversial advertising for Benetton in the 1980s and 1990s, with pictures of priests kissing nuns and AIDS sufferers to sell Sloane Rangers brightly coloured knits.
Each week, the photographers visit a different city for their assignment. The first episode saw them in Rome and you'd rightly assume that anywhere so magnificent would have brought forth some spectacular results. Unfortunately not. They may as well have been in Rotherham for all the romanticism their respective pictures conveyed.
The only photographer who gave us anything approaching relevant was Laura from Germany whose images apparently always involve her in some sort of self portrait, so in this instance she shot herself in the Trevi fountain in a tribute to Anita Ekberg from Fellini's La Dolce Vita.
We can only hope for greater inventiveness this week when the photographers find themselves in Berlin.
Say what you like about this show, you must admit that the casting of the host is inspiring.
If she'd been alive, you could have imagined Princess Diana hosting it. Undoubtably having maintained her position as the most photographed woman in the world, she would have been perfect.
In her place, however, we have Isabella Rossellini, who remains radiantly beautiful in her mid sixties and floats in and out of shot as if on a 1950's movie set once inhabited by her mother. She exudes a level of sophistication the programme perhaps doesn't deserve, but no matter. If you ignored everything else about it, Master of Photography would be worth tuning into, if only to witness such style and grace in action.
As an added bonus, along the way, you may actually learn something new the next time you take a picture or two. "Whoah, so that's the lens cap?"