I don't think I've ever made this complaint before but The Art of Lee Miller, a centenary celebration of one of the most famous women in surrealist art that is about to open at the V&A, would be better if it included more nude images of the artist. It begins with a set of photographs of this favourite subject of the modernist greats, from Edward Steichen's romantic Lee Miller in Sun Hat (1928) to a deliberately overexposed portrait by the brilliant surrealist Man Ray that transfigures her profile into something metallic and not quite of this earth. It's a beautiful image of a beautiful face. But when I looked through a volume of Man Ray pictures afterwards, I found almost endless studies of Lee Miller's flesh: he dedicated an entire session to her breasts, portraying her naked torso from different angles then radically cropping to show just the isolated, soft-focus bosom.  Another time, he photographed her in a see-through gown surrounded by her own flickering shadows. Then he shot her breasts again, in a meshed fragmented light, cropping off her head. Then a renowned image of her throat and neck.  Only a fraction of these photographs appear at the V&A, because this is an exhibition of The Art of Lee Miller, not of art that objectifies Lee Miller. Yet it would be a better, less prissy experience if it were more ready to acknowledge that Miller's body was what made her central to modern art in the age of Picasso, Cocteau and Man Ray. As it is, it begins with that superb Man Ray portrait and ends with a painting by Picasso - because how can you avoid the fact she was one of the most avidly looked at women of the 20th century?  Lee Miller was the definitive face of high fashion at the end of the 1920s. Fashion took her from Poughkeepsie to Paris, and in Paris she met the surrealists: soon she was cast as a living classical statue in Jean Cocteau's 1931 film Blood of a Poet, screened at the exhibition. Cocteau was a maverick in a French art world divided into factions. For some artists after the first world war, the tragedy of the trenches demanded a "return to order", a restoration of sanity and reason, for which the true and proper aesthetic was that of Greece. Cocteau poised his art between this classicism and the surrealist movement, which held conversely that human liberation demanded the tranformation of reason by dreams, love and the erotic.  It was Cocteau who recognised that Lee Miller had the perfect look for that cultural moment - a libidinal statue, a surreal goddess. Look at the early photographs of her in the V&A exhibition. Her hair is short, her makeup has an art deco gloss, but she's more like Athene than a 1920s flapper. At the same time, even in the early lyrical pictures taken by Steichen, you sense a dark sexuality perfectly calculated to turn on the surrealists. Miller's look made her the ideal object of desire for the surrealist movement - but she was also an active surrealist photographer whose art meditates on what it is to look and be looked at.  Surrealism was the most open of all modernist movements to women artists before the 1960s. It empowered Frida Kahlo, Leonor Fini and Dorothea Tanning to paint themselves into art history. In this exhibition there are Miller's photographs of her friends Dora Maar - a strong melancholy portrait of the artist who became Picasso's lover - and the British artist Eileen Agar, photographed as a shadow against the florid architecture of the Brighton Royal Pavilion.  Feminist scholarship has put these women back into the mainstream of modern art, so much so that every surrealist exhibition comes loaded with their works - and a backlash has begun. It's fashionable, almost de rigueur, for critics to pounce on the surrealist women, to point out that Frida Kahlo wasn't that subtle a painter, that none of the women photographers in the surrealist movement matched Man Ray. But if you go down that road you may as well dismiss surrealism - for it is in its nature a generous and baggy phenomenon. Is any surrealist art worth much if you weigh it against Cézanne? Yet surrealism does matter, because its humane recognition of the reality of desire makes it the only political avant-garde movement of the past century whose ideas are still contemporary.  This exhibition makes a passionate claim to include Miller in the surrealist pantheon as an artist in her own right, not just a famous "muse". Yet it just doesn't add up as an argument for Miller the great photographer. When she went to Paris she became Man Ray's lover. She lived with him for three years and got him to teach her everything he knew. That was a lot. Man Ray invented and developed a vast battery of special effects. At once fantastic and raw, his photographs are mostly about sex. Miller's own surrealist pictures focus on rat's tails, on a plant pot on a balcony, on organic-looking rocks on a beach. But none of these pictures seem especially driven - there's a lack of true surrealist shock because they are slightly contrived. Anyway, she doesn't stick to a surrealist method but tries out different techniques. It gets much worse when she sets up a studio in New York. The surrealistic celebrity portraits taken by Miller in Manhattan are the only really boring things here - you can see why she gave it up and emigrated to Egypt. There, the catalogue claims, she took "some of the most haunting images of Egypt in modern times" but it's hard to see how her pictures of the desert improve on thousands of examples of decent travel photography.  The thread of an artistic trajectory is unspooling here. From Man Ray to travel photography? OK . . . and then she returns to surrealist Europe in the 1930s, takes portraits of avant-garde friends, but as soon as you think she's regaining her stride, she's in Romania, shooting more travelogues. Then came the second world war. As a war correspondent for Vogue she was able to document the front line from an unexpected point of view, focusing on nurses in the Normandy landings and taking a chilling - and surreal - portrait of a Nazi girl who has committed suicide as the Allies approach and lies like a waxwork in a Leipzig house. Miller published her photographs of Buchenwald in a 1945 Vogue spread headlined: "Believe it."  Few photographers ever achieve the stylistic integrity of high art. It's so hard, in a medium that is constantly expected to be instrumental. Like a journalist, a photographer has to adapt to the job in hand. Miller was a very good photographer but there is no utterly distinctive or consistent artistic vision pervading her oeuvre - nothing except high technical quality to connect her views of the desert with her portrait of herself and Picasso as old friends reunited in liberated Paris in 1944.  And yet ... this isn't a disappointing exhibition, and Miller is by no means some minor, puffed-up figure. She leaps out of her age into ours, and you leave wanting more of her. Lee Miller did look amazing, in a way that captured a moment. She was, more than anyone else, the face - and body - of modern art in France in the Picasso age. Her own art comes to life when she attempts to comprehend that experience: here is an icon who turns the camera the other way. Her self-portrait from a series of shots called Lee Miller par Lee Miller is impeccably dignified, a deliberately simple image of a woman so often subjected to visual transformations by modernists (compare it with the Picasso painting at the end of the show).  Even when she's photographing the desert, you might think she's meditating on what it is to be looked at. Her most beautiful surrealist photographs are nudes. They are sumptuous yet nearby hangs a pair of pictures of a severed breast laid out on a white dinner plate with a knife and fork to either side. It's a gory materialisation of something Magritte might have painted as a philosophical enigma.  The art historian Whitney Chadwick has seen this as an angry riposte to Man Ray's objectifying images of Miller's breasts. But surrealist art is full of violent, dislocated, carnal images. She's probably trying to create a surrealist shock, but the image is too tragic. Maybe it is an example of the discovery in some surrealist art of a base, grotesque level of reality, an undredeemable psychic sewer, that art historians have labelled the "formless".  No surrealist man or woman thought eroticism was wrong. Sex was sort of the point of the entire movement. If you can't follow the surrealists into their insidious daydreams you probably shouldn't bother with them.  My favourite photograph of all by Miller is shown here among the pictures she took after returning to Europe from Egypt. It's a funny and touching record of a group of surrealists at a picnic near Cannes in 1937. It reminds you of the German critic Walter Benjamin's characterisation of surrealism as "the last snapshot of the European avant-garde". They're relaxing under the trees. Bottles, glasses and plates all emptied. The sun breaks through the leaves in bright dapples and their pleasure broadens out in a collective smile. The three men are all well covered-up, but the two women in the picture are bare-breasted, in fact entirely nude except for towels over their laps. What does it mean that Paul Eluard, clothed, flirts with his wife Nusch who's nude, while Man Ray in a white cap and shirt sits next to bare-chested Ady Fidelin? Are they all aware of the parallel with Edouard Manet's similarly unequal 19th-century picnic scene Le Dejeuner sur l'Herbe? What does Miller think, as she takes the picture? They're all laughing. It's 1937. Picasso is painting Guernica. Dora Maar, off camera, is crying.  · The Art of Lee Miller is at the V&A, London, from Saturday. Details: 020-7942 2000.
Lee Miller was the world's most fashionable face, and muse to some of the 20th century's mightiest artists. But was she also a great photographer in her own right? By Jonathan Jones.