Green Days: Dinosaur and I

Green Days: Dinosaur and I is a 2011 South Korean animated film. Without the high-tech computer graphics and three-dimensional techniques that dominate the animation industry, the film was hand-drawn in pencil, with 14 animators using 100,000-plus sheets over a period of 11 years. It premiered at the 15th Busan International Film Festival in 2010 and competed for the top prize at the 2011 Annecy International Animated Film Festival.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.