This is an original oil painting by Latin American artist Hector Campos. He was commissioned to paint the Costa Rican village of Biolley, where the movie takes place.
Photoshopped to reflect the actual geography of the village: Raised valley to a hill, adjusted daytime hue to a more dramatic nighttime atmosphere.
I extended the artwork's background for seamless horizontal parallex scrolling. Check it out: asmallsecitonoftheworld.com