Some people say that radio has the best pictures, because the listener creates the visuals in his/her head. A still image leaves nothing to the imagination - or does it?
Of course there are many factors that create a compelling photograph, but there is a type of picture that can only be described as minimalist, because it gives just enough visual information for the viewer to create the rest of the scene in the imagination.  Basically, the photographer shows a detail that gives an impression of the whole. The picture entices us not with what we can see, but with what has been left out.

This might seem easy. For example, I could shoot a leaf lying on the floor with the aim of triggering an image of a tree in the viewers mind. But it doesnt quite work like that. For a start, a leaf lying by itself wouldnt trigger the image of a tree; there would need to be an extra factor. In addition these pictures rarely work unless there is a human element, however tenuous, to bring the picture to life.  Finally, the leaf picture would be very dull. The successful minimalist photograph needs to be a compelling photograph in its own right, through the elements contained within it or the composition.

Like many areas of photography there is no formula, because every situation is different. Success will rely on the photographers power of observation to spot  detail in a context that creates exactly the right links, giving the viewer a spark to fire the imagination.

Close up pictures of hands are often used to give an impression of the whole person or a situation, but wouldnt work with any old pair of hands. David Grays photograph, above, demonstrates this very well. A Chinese worker with his hands behind his back pauses while working on a railway link for next years Olympics. The gloves are so tattered, and his fingers so grimy, that they tell us how hard the man works and because he seems to be overdue a new pair of gloves we are given a clue about his working conditions.

This type of image doesnt necessarily need a human body part to actually be in the picture. In Lee Celanos picture above, showing the shadow of democratic presidential candidate Barack Obama at a public meeting, we cant see the man himself, but because he is holding a microphone  it is immediatley clear that he is addressing an audience .  The atmosphere is increased by the distorting effect on his hand by the curtain, as it appears to creep tantalisingly towards the hand of the secret service agent, which itself is a detail to further fire the imagination.

Shadows tend to be a recurring theme in this type of photograph. Brian Snyders photograph shows a youngster using dance to develop self-esteem, creative expression and imagination. The image is reinforced by the leg dropping in from the top of the picture, and the two elements work together to help us create our own picture of the part of the scene that falls outside the frame of the photograph.

Damir Sagoljs photograph of a US soldier patrolling in Baghdad doesnt need additional information as the shadow is so detailed. The seemingly deserted street works with the shadow and effectively conveys a sinister atmosphere. This gives us an impression of the fear felt on those streets, whether it is felt by the soldier or the local people. This impression is much more powerful for being left to our imagination. Also note the composition, and the way the eye is drawn from the right of the picture to the left by the direction of the weapon and the white barriers.

Sometimes the familiarity of the person in the picture is essential for us to make sense of it, such as this photograph by Jessica Rinaldi, showing a silhouette of a figure we instantly recognize as Tiger Woods. But the story is told by the body language, which suggest that Woods is not having a good day. The shaft of the club adds the finishing touch to the image.

The image above by Yannis Behrakis, of Israeli security forces taking cover behind their shields during clashes in the West Bank city of Hebron, would have been a meaningless still life picture of shields if it wasnt for the hand, introducing the human element into the picture and bringing it to life. But the hand makes the picture appear forlorn, and we are left to draw our own conclusions about what is happening out of sight below the transparent part of the shield.

This photograph by Pascal Lauener, of a beach volleyball game between the US and South Africa, is nothing more than three hands and a ball. But because of the positioning of the hands and fingers, and the straining muscles, we know that the players are competing ferociously and its easy to imagine the action taking place beneath the hands.

Finally, as an exception to the human element rule, this well observed and well shot photograph by Darren Staples,  of the helmets belonging to members of the Indian cricket team sitting on the field during the fourth day of the second test match against England,  gives very little away, and leaves so much to our imagination.  Are the players having a break? Why did they place their helmets in a line?

There are many subject matters that grab our attention or draw us into a photograph, and by far the strongest is the human face. It is because a facial expression betrays what the subject is experiencing, and triggers empathy within ourselves. The more extreme or unguarded the expression, the more compelling the image becomes.

Although we feel sad when we see a photograph of somebody suffering, it is sometimes possible to experience a certain joy from looking at the expressions of others. In my view this is because, regardless of the size of the human population and beyond all expectation, each face and expression is unique.

Below is a small selection of photographs of the human face taken from the Reuters wire service of the past few days, which concisely shows a variety of human emotions that are betrayed by expressions. Taking a global snapshot like this brings home the fact that regardless of nationality or race, we are all part of the human family.

Alicia Contador, sister of Discovery Channel team rider Alberto Contador of Spain, cries as she celebrates his victory in the 94th Tour de France in his hometown of Pinto, outside Madrid, July 29, 2007. REUTERS/Susana Vera

Japanese Prime Minister Shinzo Abe bites his lip during a live television appearance at his Liberal Democratic Party headquarters in Tokyo July 29, 2007, after an upper house election in which his conservative ruling camp suffered a devastating defeat. REUTERS/Issei Kato

Fans cheer at the premiere of “Rush Hour 3″ at the Mann’s Chinese theatre in Hollywood, California July 30, 2007. REUTERS/Mario Anzuoni

Chief Khmer Rouge inquisitor Kaing Kek Ieu, better known as Duch, is seen in Phnom Penh in this handout picture released on July 30, 2007. Duch appeared before Cambodia’s “Killing Fields” tribunal on July 31, 2007, the first of Pol Pot’s henchmen to be questioned over the deaths of an estimated 1.7 million people. Duch has confessed to committing multiple atrocities during this time as head of Phnom Penh’s notorious Tuol Sleng, or S-21, interrogation centre.

Purnima Poddar, an HIV affected girl, takes part in a protest march against negligence in the field of Thalassaemia and HIV/AIDS treatment and management in the government sectors, in the eastern Indian city of Kolkata, July 30, 2007. REUTERS/Parth Sanyal

A resident with the colours of an Iraqi flag painted on his face celebrates in Basra, 550 km (340 miles) south of Baghdad, after the Iraqi team won the final game of the 2007 AFC Asian Cup soccer tournament against Saudi Arabia in Jakarta, July 29, 2007. REUTERS/Atef Hassan

There are many types of photograph that fall into the category of the marmalade dropper or the ‘cornflake dropper’. The phrases refer to astonishing pictures, or stories, that cause the reader of her/his morning newspaper to drop the marmalade or cornlflakes in mid-bite. More often than not it is the unexpected nature of the subject matter within the photograph that causes the extreme reaction. There are lots of examples, but the ones that always catch my eye are the photographs that combine luck and skill, resulting in an image that appears both familiar and yet unfamiliar at the same time.

By its nature a photograph is two dimensional, and gives the impression of a third dimension through light/shade and perspective. But sometimes the everyday elements within the frame come together to create something unfamiliar, creating, in my view, a fourth dimension in the image, almost an optical illusion, stopping us in our tracks and enticing us to take another look and another.

These photographs are quite rare, because in order to work they have to be perfectly composed. Given the scale and scope of the Reuters picture operation I was able to find three such photographs shot within a 24 hour period.

The first photograph, by Denis Balibouse, shows US golfer Paula Creamer marking her ball in the 14th women’s Golf Masters in France. We immediately recognise what we are looking at, but the more we look the less familiar the image becomes.

The photograph of Barcelona’s Thierry Henry, by David Moir, diving for the ball in Edinburgh makes us look twice as his head appears to be replaced by the ball.

Synchronized swimming always makes striking images, and in this photograph by Daniel Munoz the legs of the U.S. team competing in Rio de Janeiro create an interesting pattern.