A scenario simulation system for a multimedia device is disclosed. An outline detection device separates a plurality of images from an image source to a plurality of foreground and background images which are stored in a foreground storage medium and a background storage medium respectively. A foreground selector selects a foreground image, and a background selector selects a background image. An image mixer mixes the foreground image with the background image as an output image. An image output module transmits the output image for replacing a real image to a remote multimedia device.