Green Screen is a funny application for your Android mobile phone that allows you to create, in real-time, the "Chroma Key" or "Green Screen" effect when you are taking a photo. The Chroma Key is an effect often used in movies, interviews and weither forecast broadcasts, where someone (e.g. the meteorologist) stands in front of a green/blue screen, and then a picture (e.g. the weather map) is added on those parts in the image where the color is green/blue.