Family photo albums are haunted by the ghosts of our past. They encapsulate our most cherished reminiscences, arranged in a neat chronological sequence. Hindsight allows us to relive our fondest memories the way we would gladly have lived them then.

It can happen in the best of families: the conversation falters, tempers fray. Whenever I notice that something's brewing, I get out the family photo album. Everybody gathers round, and there are gasps of surprise and glee as recognizable facial features appear on pictures of babes in arms and budding adolescents. The lure of the documented past is an unfailing remedy for tense moments. After all, snapshots bring back times when we laughed together and loved life.

Personal photographs capture happiness for ever and a day, releasing it whenever the album is opened. The images may be blurred or faded or overexposed, but they never fail to work because they impart a little of that intensity that belongs to bygone times - a living moment frozen in its tracks. A photograph can be a fairy-tale scene compounded of joy and affirmation caught on high-gloss paper. Just as grandmothers will put their savings into nest-eggs for their grandchildren, so mothers start a photo album for their offspring - biographical savings to be cashed in again and again later in life.

London art critic John Berger defines the difference between the camera and the human eye this way. The camera, he argues, can select and perpetuate a single scene from a constant flow of scenes, rescuing a given image before it is inexorably swamped by a flood of succeeding images and preserving it in immutable form.

This poses the question: what took the place of photography before the camera was invented? The answers that occur to one on the spur of the moment might be on the lines of: copper engravings, drawings, paintings ... But on second thoughts we should perhaps reply: memory. Photographs are there to "open the floodgates of recollection," in Erich Fromm's words, to "resuscitate the feelings". Although "for most people photographs evoke alienated memories". The history of photography and the history of tourism go hand in hand. In the days before photography, travelers kept journals and sketch books. But it was the camera with its ability to reproduce images precisely that first made it possible to capture the visual evidence of impressions and experiences - at least as the aggregate of individual moments in time. Travel photography tends to serve as what we might call a "selective visual memory", preserving culturally standardized (in other words, conventional) highlights which are then classified as the key experiences. A simple example will help to clarify the point. You might be looking at a beautiful stretch of countryside and decide to photograph it. Once you put a camera to your eye, you are no longer capable of registering any deep emotion about the landscape because your attention will be divided between taking in the scene and handling the camera. In effect, you will be forfeiting part of the immediate experience for the sake of your later memories.

By perpetuating even the most trivial times and places, you are transforming them into status symbols of your lifestyle. Each photo testifies, now and for all times, to your impressive resources of leisure time. You had time on your hands in Africa, on the Eiffel Tower, by a lake in Finland ...

It is in the nature of personal photographs that they make the fleeting moment recoverable, prolong the transitory experience, bring back the thrills long after they have faded, and lend permanence to the memorable moment. Preservation, then, is one of their functions. Public display is another.

Hey look, that's me! I was in Rome at Whitsun. And that's me in Caorle. If the "pictorial archaeologists" of future ages unearthed only our family photo albums, they would encounter little else but smiling figures stiffened by the corsets of their daydreams. The scenes of our every-day lives seldom find their way into our photo albums. What we glimpse through the view-finder belongs to a more glamorous world of travel and good times - memorable events like weddings, christenings, the first day at school, an endless succession of birthdays, outings and vacations. Snapshots are the mosaic tiles that make up a pictorial biography, imposing a tidy chronological sequence on a life history.

Some adults studiously avoid appearing on snapshots, but few manage to escape being immortalized in childhood. Inveterate family photographers have a habit of pouncing on children as their favorite motif, preserving for posterity the infant's first tottering steps and the slow but sure transformation of child to adolescent to adult. This pictorial documentation becomes a heritage, a reminder of the way we were. A sure way to steer any conversation into safely sentimental channels is to bring out the family photograph album. Even the way we were, though, undergoes subtle changes in our minds. The more we cling to photographic memories, the more our other recollections blur. The French literary critic Roland Barthes makes the point succinctly: "My friends were talking about their childhood memories. They still had some. I had just been looking at my old photos, and my memories of childhood were gone."

It was long customary for professional photographers to be entrusted with the momentous task of making formal portraits of the younger generation. The children would be ushered into the "studio" and put on earnest expressions as they stared into the camera lens. The portrait photographer would later touch up the coloring and the highlights and generally prettify - all part of his duties as a socially recognized "master of ceremonies" for all solemn occasions. Times and lifestyles have changed, though, leaving the professional portrait photographer an endangered species, a tragic figure in the drama of relentless social upheaval that will eventually consign even him to the role of a mere memory. His place is being usurped by coin-operated snapshot machines and self-proclaimed amateur photographers armed with ever more affordable cameras producing ever better photographs.

It is barely surprising, then, that professional photographers are allergic to the word "snapshot". The "snapshooters" are edging them out of business and will ultimately make them redundant. Each camera owner is his own master of ceremonies, and families no longer need the photographer's services to glorify the way they are.