You might never have wondered what it would be like if Clint Eastwood had played Wolverine or Leonard Nimoy got the part of John McClane in Die Hard. I know I haven't.
But nevermind, it's already been done for us and the results are intriguingly good.
Illustrator Sean Hartter, 38, has been reimagining classic film posters but with retro casts in them for the past three years. His Alternate Universe Movie Poster project encourages other artists to come up with their own designs, and the idea has spread around the globe. Many of them are arty reinterpretations of a film's theme, while others are clever pastiches of old styles of movie poster.
Among them are works by New York illustrator and designer Peter Stults, 29, who has also cast Al Pacino as Wolverine, along with Dean Martin, Jerry Lewis and Jack Lemmon in The Hangover. Other posters include Charlton Heston and Harry Belafonte in Pulp Fiction and Frank Zappa, Iggy Pop and David Bowie in The Big Lebowski.
Stults even makes the posters look old by Photoshopping fold marks and signs of ageing on to them. In the alternative movie world Jean Luc Godard has directed Trainspotting with Terence Stamp and Michael Caine in it, and Marilyn Monroe and John Wayne are the stars of Kill Bill.
Hartter, from Massachusetts, says dozens of similar sites have sprung up around the world, many doing alternative posters of yet to be released films. At the moment Christopher Nolan's upcoming third Batman film is occupying a lot of designers minds, with predictive poster versions of it popping up across the web.
Hartter told me: "I draw my inspiration from exploitation posters from the 60s and 70s, and the almost mythic stories of movies that could have been. Things like Sylvester Stallone almost playing Han Solo in the original Star Wars, or David Lynch being courted to direct Return Of The Jedi.
"I guess what I'm trying to impart is the sense that you might see these posters in the window of a sleazy urban movie theater, sun bleached and neglected, brittle from age. But instead of starring Z list actors and concepts no one has heard of, they are adaptations of comic book story arcs, blockbuster films that never became blockbusters, fantasy novels that are, in reality, impossible to actualise into films.
"I've always been fascinated by foreign versions of iconic film posters in the US, and alternate posters that were never used or were only used in a limited fashion. I'm also a huge fan of the pastiche photo manipulations of Terry Gilliam. I grew up watching Monty Python and the way Gilliam utilised photographs to create these bizarre worlds made a massive impression on me.
"My style is a little wonky but I really try to adhere to rules I've learned studying the way they assembled posters in the heyday of exploitation and grindhouse films. I've designed a few hundred posters for events and websites, or just for my own satisfaction."
Hartter has made friends with a lot of artists and admirers due to the distribution of his work across the web and the world.
He adds: "Some people don't like my work and that's fine. A bigger percentage do like it and respond to the tongue in cheek attitude that is prevalent. I try and impart a little bit of humor and a lot of nostalgia. I'm very serious about the way I create the posters but at the same time they are a parody, and definitely the antithesis of modern poster design.
"I use Photoshop too, but I tend to use it as if I'm cutting out paper or photographs and assembling them. I hand draw things too but approach this method in the same fashion."
Stults, who has been mocking up modern film posters as a hobby with pals for about 10 years, was shown Hartter's site by a friend and began doing his own alternate movie designs and sometimes adapting Hartter's existing posters.
He said: "While studying film & digital media at UC Santa Cruz and farting around on photoshop in my bedroom, I began dabbling with the idea of "made up" movie posters. Back in 2002 to 2004 my friends and I toyed around with silly ideas; taking song titles and using those as stepping stones or someone would say 'I want to see this actor and that actor in the same film' or we would do the 'It's Mulholland Drive meets Jumanji' film summarising approach to help create a movie concept.
"A while back a friend of mine forwarded me a site where an artist had made posters of films that, title wise, we were familiar with, but there was a slight difference; they were remade as if they belonged to a different era or a different genre.
"The name of the movie was there, but the actors were different, the style was different, and I loved the concept. So I went forward with this theme; what if movies we were all familiar with were made in a different slice of time? Who would be in it? Who would direct it?"
Stults was a typical comic book obsessed teenager who grew up in Santa Cruz, California, drawing his own superheroes.
He said: "The 'what if' idea Sean created is an inspiring tool. The creativity is very lively right now: Sean's alternate universe, the fake Criterion Collection covers, posters for movies that exist in fictional books, even the mash-up trailers on youtube.
"I've always had a passion for film. I worked at a Hollywood Video for a while and every night I was taking home movies to watch. Movies of today and yesterday I have an appreciation for.
"The look and feel of the movie posters of previous decades have such a unique art to them. It's a style I enjoy playing around with. When it comes to making the posters and contemplating ideas, I sort of think of movies I've recently seen or simply enjoy and then just wander in the 'what if' world. Ricky Nelson in Donnie Darko, Monty Python's Shaun of the Dead, Robert Redford & Dustin Hoffman in Fight Club. There's also some film history research involved too. Who was a leading actor at a certain time, what names were popular in terms of directors, and, of course there's also the absurd."
To see the full range of alternate movie posters check out Hartter's and Stults's respective blogs.