Everybody is familiar with the Drew Struzan poster for Back to the Future (a piece of which is pictured above), which finds a panic-striken Marty McFly looking at his watch while he stands at the open door of his time-traveling DeLorean. The image was used for all three films in the trilogy, adding characters (like Doc Brown for the Part II poster) or details as the new films demanded.
Struzan actually worked on some very different takes before he finally settled on Back to the Future's final one-sheet. Alan Cook's blog has some great concept posters for all three films, and I was surprised that I'd never seen these "rejected" Back to the Future posters for the first film before today. Strangely, they all seem to date the film in the 80's, whereas the final one-sheet has a more timeless, iconic quality. That's probably a big part of the reason why they ended up using it.
You can see all four unused concept posters after the jump.