1. A method implemented in one or more computing devices, the method comprising: obtaining an image of a scene; generating, based on the image, a 3D representation of the scene; identifying, based on the image, a light model for the scene; inserting one or more objects into the 3D representation of the scene; and rendering, based on the light model, the 3D representation of the scene to generate a modified image of the scene including the one or more objects.