Faking photos and animations just got easier - complete with shadow and reflections.

From PopSci.   
A simple programming tool created by Kevin Karsch et al can build a model of a scene in a two-dimensional photograph and insert a realistic-looking synthetic object into it. Unlike other augmented reality programs, it doesn’t use any tags, props or laser scanners to model a scene’s geometry — it just uses a small number of markers and accounts for lighting and depth.

The page links to a video showing inserted animations too.  Geometry of the scene and light sources are quickly dubbed in.