Charles Saatchi's exhibition, The Triumph of Painting, hints that his love is for the image rather than the medium, writes Aidan Dunne

To mount a series of three enormous exhibitions and call them, collectively, The Triumph of Painting, is brave, or foolhardy, or arrogant, or perhaps just naive. Or all of the above, given that the man behind the project is Charles Saatchi, that the work is drawn from his own collection and is being shown in his own gallery in the heart of London.

What does The Triumph of Painting mean? It partly means the survival of painting, given its various detractors and the number of times it has been declared dead. As the Chinese filmmaker Zhang Yimou once said in another context: "To survive is to win." With the invention of photography, it seemed to many observers that painting's days were numbered. More pointedly, conceptual artist Joseph Kosuth seems personally affronted by the fact that painting is still around, and he is by no means alone. Yet painting is around, and not just as a nostalgic pursuit. It seems to be more than equal to the most pressing questions attendant on the making of art in our time.

This is where Saatchi's triptych comes in. The shows are not simply or solely about glorifying painting or, as the more cynical observers might be inclined to think, about boosting the stock of the collector's latest batch of acquisitions. There is a thesis behind them, and it goes something like this: to survive, painting had to learn how to deal not only with the photographic image, but with an environment that is, in a sense, all image.

That is, an environment composed promiscuously of what we think of as ordinary, three-dimensional reality and the myriad forms of manufactured signs and images that permeate every aspect of our world.

The defensive attitude that painting owes allegiance to reality in the classical, conventional sense - that is to say it must eschew photographic images and other trappings of modernity - held considerable sway for a long time.

It was a way of preserving a territory, a sphere of influence and holding out a claim to authenticity. But that attitude has been well and truly overtaken by the pragmatic recognition that things have changed.

There is a general, strategic point to The Triumph of Painting. But the project is also extremely partial and contingent on Saatchi's own taste and inclinations as a collector. The first, current show marshals work by just six artists, presented as the senior figures whose influence reaches out in various ways to the more numerous artists in the subsequent shows. To facilitate our reading of the bigger picture, so to speak, all three shows are anthologised in one hefty volume.

The choice of the initial six is oddly arbitrary and uneven in the sense that not all are strongly represented. A key role is apportioned to the late Martin Kippenberger, a once truculent presence who the art world has taken to its bosom in death as it never quite could in life.

Kippenberger rose to prominence with the emergence of Neo-Expressionism in the late 1970s and early 1980s.

He worked in a bewildering range of styles and forms and in numerous capacities. His role in cultural life was to be pushy, disruptive, provocative, an irritant. It is entirely possible that his current high standing is an overreaction to his prior neglect, though he was never quite neglected because he was impossible to neglect - in the sense that he was always there, always active, always in your face. In any case, young artists understandably warm to his punkish attitude to the art world.

Like them, Saatchi clearly likes his noisy iconoclasm. To judge by the general tenor of his collection, it's a quality he warms to in artists generally. There are exceptions, though. Most of the work to follow is indeed exuberant and noisy, but those terms don't apply to at least two of his initial five artists, Luc Tuymans and Marlene Dumas. And both are rather sparsely represented.

The best Dumas is a big, eerie close-up of a baby's head. Tuymans' pale, exhausted-looking images address a state of faded, diminished presence, a thinning of experience which might refer directly to images' increasing distance from any concept of the real. That is, we are consigned to dealing with an endless chain of signifiers, indefinitely postponing any encounter with a notional signified.

Yet Tuymans' quietly insistent paintings do have considerable presence.

In a way the work of the Austrian artist Hermann Nitsch is all presence. Stemming from his elaborate, bloody, orgiastic performance events, the "paintings" consist for the most part of copious spatter patterns of - one presumes - red paint on canvas, though Nitsch did use animal blood as well during the performances. The paintings come across as being dated relics of performance.

Presumably Saatchi likes their gory theatricality, but their sensation value seems long faded. The same goes for Jorg Immendorff, like Kippenberger a Neo-Expressionist, whose paintings are crude and bombastic and never really seemed to be anything else.

The remaining artist of the first six, Peter Doig, is one of the most interesting painters to have emerged in the past 15 years or so. Doig lives up to the claims made for the show as a whole. His often big, ambitious works deal matter-of-factly with a world of mediated imagery including, for example the film Friday the 13th, picking up on the flavour of popular culture and brilliantly exploiting our familiarity with it in his richly eclectic, hybrid compositions.

It wouldn't be fair to prejudge what is to come, but it seems safe to predict that things will get even patchier. It's not that Saatchi has gone for marginal or unknown figures. On the contrary, pretty much everyone included in Part Two has a substantial CV and healthy market rating. With significant amounts of work by such painters as Cecily Brown, Dexter Dalwaood, Dana Schutz and Tal R, you can be sure you're going to have something worth looking at, enough to create an overall impression of excitement, let's say. But by the time Part Three comes around, proceedings may begin to resemble a student show: lots of artists clamouring for attention on the basis of narrow stylistic signatures.

In fact there's something slightly disturbing about the way Saatchi appropriates the voluminous term "painting" and crams it into the parameters of his own limited vision. One begins to wonder if those abstract works by cooler sensibilities that turned up in the early days of his previous Gallery in Boundary Road were Doris Saatchi's contribution to the proceedings.

One can certainly conclude from this and the shows to come that Saatchi's love is for the image rather than the medium. He is drawn to work encapsulated in a representational image, preferably an image with a bit of a charge, some shock value, something catchy about it. This means that The Triumph of Painting is, oddly enough, really The Triumph of the Image.

The Triumph of Painting: Part One is at the Saatchi Gallery, London until July 3. The Triumph of Painting, with essays by Alison Gingeras and Barry Schwabsky is published by Jonathan Cape at £35