Turn on your computer, and there's Justin Bieber, hair swept back, white T-shirt rumpled at the shoulder to show off his tattoos, chunky watch prominent in the black-and-white frame, ­cigarette dangling from his mouth.

He's the epitome of James Dean cool.

Of course he isn't. Dean didn't need faddish ink on his arms and his watch wasn't so ostentatious. Bieber is just a fanboy in an Instagram selfie, purposely trying to replicate the outsider image because it doesn't exist in his natural DNA.

"This is James Dean inspired," the singer wrote beside the photograph he uploaded a couple of weeks ago. "Don't ask me if I smoke ciggys cuz I don't." You couldn't invent a clearer example of the vacuous, focus-group nature of 21st-century pop celebrity.

But what of Dean himself? Is his legacy still as potent in 2014 as Bieber's appropriation of it suggests? Killed in a car crash at the age of 24, with only three feature-film leading roles under his belt - East Of Eden, Rebel Without A Cause, Giant - the cult of James Dean is built more from off-screen fragments than what endures of his celluloid work.

We think we know Dean's life story, probably because there are more documentaries and biopics about him than films he actually starred in. Born in Marion, Indiana in 1931, he lost his mother to cancer when he was nine and was brought up by a Quaker aunt and uncle rather than his father. While studying at the Actors' Studio in New York, he had some movie walk-ons and TV bit parts before director Elia Kazan, looking for "a Brando type", took a gamble on him for the role of Cal Trask in East Of Eden. Less than 18 months later Dean was dead, a broken body inside his Porsche Spyder on Route 466 in California.

Kurt Cobain, Jim Morrison, Amy Winehouse: an early exit becomes part of the allure. The James Dean we see in our mind's eye walks towards us in a long black coat, shoulders hunched and brow wrinkled, as rain turns the Times Square pavement into a dark mirror. But have the film performances dated? Are they trapped in an era of naturalistic mumbling and indulgent rants when the older stars around him were still doing proper acting? Are they, in other words, the Jack Kerouac novels of screen acting?

Having watching all three features again, ahead of their upcoming cinema re-release in digitally restored prints, I don't think so.

Consider the emotional complexity of Cal in East Of Eden; desperate for his father's love, reaching out to the whore-mother who became absent early in his life. The vulnerability of Dean's performance doubtlessly comes from personal experience but it takes a remarkable talent to make cinematic sense of that in front of a camera. It's the manner in which Dean offers his emotional self so completely to this film that sets East Of Eden apart and, as is evident from the acting style of Raymond Massey, playing Cal's father, this was still something new and unsettling for the Hollywood establishment.

Rebel Without A Cause secured Dean his iconic status, but of the three it's the film I have most problems with. Unlike the earlier 20th-century "period" settings of East Of Eden and Giant, it wears its contemporary themes like badges of pride. As such, it almost becomes a 1950s teen exploitation movie, with its gangs, knife fights and "chickie" runs. Some of Dean's outbursts seemed as consciously designed to dominate the frame as Jim Stark's now iconic red jacket.

And yet, for all its embracing of 1950s fads, Rebel Without A Cause isn't a straight genre film. Something genuinely intriguing grows between Jim, Judy (Natalie Wood) and Plato (Sal Mineo) that offers an alternative to the nuclear family of their parents' generation - although the outcome is not exactly happy.

However, it's what Dean does in Giant that suggests, had he lived, he could have gone on to become one of Hollywood's greatest actors rather than a generational symbol whose potential was barely tapped. As ranch hand turned oil baron Jett Rink, he more than holds his own in a prestige picture alongside big-name stars, often stealing the scene from under their noses through physical movement alone: his toying with a length of rope when offered money for the land he's been left in a will, slouching in the back seat of a posh car with his feet on the front headrest, stalking out his patch then surveying it on high from his battered windmill.

In the second half of the film - a soapy prototype for TV show Dallas with its love triangles, personal feuds and Texas backdrop, albeit enhanced by a potent attack on racism - Dean has to play a character decades his senior. The facial make-up and grey hair look hokey now but his vocal slurring, his body language and the conflicted feelings he projects turn Rink into an isolated, pitiable figure, the Method actor's bridge between Charles Foster Kane and Vito Corleone.

Three films, three men aching for the thing that's just beyond their reach - parental love, adult understanding, social acceptance. We tend to view James Dean by blurring the line between the ­characters and their creator because we have no other choice: this small but entire body of work colours any sense we have of the actor and the human being he might have become.

But that body of work does exist, now in a sparkling digital format that challenges hackneyed posters and celebrity pastiches. See the films, and let James Dean speak from the screen.

Edinburgh Filmhouse screens the restored versions of Rebel Without A Cause from Friday, Giant from April 25 and East Of Eden from April 27