Johnathan Jones: Rémi Ochlik's great photograph tells truth about the Arab spring

In a moment of chaos in Libya, the late war photographer produced a rich, subtle portrait of a young revolutionary

Here is the proof that the world lost a great war photographer when Rémi Ochlik was killed in Syria this week. Ochlik was only 28 when he died but already a profound and original observer of the most dramatic events of our time – as this photograph of a young Libyan showing off a gun he has looted from the compound of Muammar Gaddafi shows.

It is the 23 September 2011, and rebels are overrunning Gaddafi's stronghold in Tripoli. This youth has come away with a gun, and poses with it as a romantic rebel. In his red beret against a wall of fire in a fervent north-African twilight, he wears white straps over a ragged shirt as he looks at Ochlik. The photograph captures a moment of excitement and impulse and unpredictability: we don't know what the gun-toting youth is saying or thinking, and he may not know himself in the heat of the moment. Behind him a figure seems to stagger with the thrill of it all as he helps carry a heavy box, presumably of more looted stuff.

The picture is full of ambiguities. Is this young hero a veteran of many battles, or has he just got swept up in the drama? Is he an idealist or an opportunist? Ochlik has captured a very human moment – a young man striking a glorious pose. It is a great image of the Arab spring, a portrait of a revolutionary that is rich and subtle. There is a tender, even sexual beauty to the portrait. This rebel happens to be good looking, slightly feminine, and the photograph has something about it of the paintings of Caravaggio in its sensuous capturing of immediate, strange urban reality.

It is a work of art. In an age of instant pictures taken on mobile phones, the role of the professional newshound photographer dashing around the world to record wars and revolutions might seem archaic. But this picture shows how an accomplished and serious photographer who has studied the methods and history of his art and has a special eye for potent scenes can contribute a richer vision than you or I would ever manage if we just happened to be there with a camera. This guy had talent, and a personal way of seeing, and it shines in this photograph. The light is extraordinary – he saw the coincidence of a building on fire and the flaming sunset, and got this youth to pose between the two, so that natural and unnatural fires are mixed in a palette of red and gold. Because of these furnaces behind him, the youth is seen by contrast in cool, dark blues.

I suppose this is what makes the photograph Caravaggesque. Just as the Baroque painter pictured young street urchins in dramatic polarities of light and darkness, so Ochlik has taken the opportunity of fire and evening to romantically pool blueness around this rebel.

It is a picture of adventure: and in that sense it might stand as a glimpse of autobiography. While the young Libyan totes his gun, the young photographer is there with his camera. Both seem drawn to the romance of the moment. The subject of the picture is proud and excited to be part of these great events. Meanwhile Ochlik has been drawn there by an adventurous impulse of his own. He photographed the Arab spring from the start. You can follow his journey in his pictures, from Tunisia to Egypt, always at the heart of the revolutionary action, then in his award-winning work in Libya. His adventure finally took him to Syria, where his determination to witness the incredible events of our century was cruelly rewarded.

Humanity and compassion shine in this picture. In a moment of high drama and chaos Ochlik manages not just to take a striking photograph but one with emotional depth. We see a life, a story, unspoken and mysterious but fascinating and individual, in this picture. The same tenderness shines in Ochlik's other work from Libya. He photographed the body of Gaddafi, and did so with a sensitivity utterly unlike more gory images that flashed around the world. In his pictures from Libya there is at once an empathy with the oppressed – it is clear whose side he is on – and a clear eye for the moral ambiguities of war. He frankly shows rebels pointing a gun brutally at the head of an alleged Gaddafi mercenary.

This picture typifies Ochlik's humane truth-telling. It tries to make us see the real, blazing, impossible drama of a moment in a war when courage and opportunism, glory and madness are hard to tell apart. It is at once heroic, delicate and warmly comic, as he responds to this revolutionary's style.

War photographers are obviously among the last romantics of the modern world. Ochlik wrote about a friend, Lucas Mebrouk Dolega, who was killed photographing the protests in Tunisia in January 2011. "Little by little", he said, his young colleague "was realising his dream, covering world news". That was at the start of the Arab spring, and already Ochlik saw, up close, proof of the risks he and other photographers were taking on the revolution's front line as it moved gradually towards his rendezvous in Syria.

Photojournalism is an art for the brave. Ochlik witnessed so much, in his short life, and left photographs like this one, that deserve to be looked at for as long as war and revolution stir fascination and fear and compassion.