“Yes, Emma, your new haircut is adorable, but we have to move on now.”

“I directed one microbudget indie feature,” Stephen Chbosky says of his previous experience as a filmmaker. “Half of it is really good.”

OK, so maybe Chbosky didn’t quite have the résumé to take the helm of “The Perks of Being a Wallflower.” But the author of both the screenplay and the source (a powerful Young Adult epistolary novel that keeps getting itself banned in high school libraries for your typical drug-sex-drinking-gay reasons) found the transition wasn’t that difficult, thanks in part to his writing style.

“I think in images, and I think in sounds. I hear them spoken when I write,” Chbosky says. “Since most of my training was in screenwriting and film, I wrote the book with movies in mind.” That doesn’t mean moving the story from book to screen was a breeze. “Because it was an epistolary novel, it was still difficult as [expletive].”

Part of that expletive-deleted difficulty arose because the novel is told solely from the point of view of Charlie (played in the film by Logan Lerman), a bookish teenager who survives high school with the help of friends Sam and Patrick (Emma Watson and Ezra Miller).

Because it’s Charlie’s story, he’s a reliable narrator in the book, Chbosky says. “In the movie, you have to earn it,” he says. “You have to write it so the audience feels the same way Charlie feels.”

The film, which opens locally Friday, allowed Chbosky to tell his story in a way a book never could.

“The one thing that really works in the film is juxtaposition,” he says. “You can show the same person as a 7-year-old boy and a 16-year-old boy in the same kitchen [simultaneously]. Those images put together were what was worth a thousand words.”

Some of those words and images might not have sat well with the MPAA ratings board — “Wallflower” contains underage drinking, drug use, sex, violence and sexual abuse — but Chbosky took steps to make sure the film wasn’t slapped with a knee-jerk R rating.

“I understood, by studying movies, the general boundaries,” he says. “I tried to tell the story that way, and the MPAA was very open from the beginning. For the most part, if a 13-year-old girl wants to get the book, she can find it. I needed to have the movie available to that person.”