use very big stills.., learn color correction (to make it look a part of the composited image) and the use of alpha channels.., stills are being used in feature film now.., done properly.., with say a 16K image.., and alpha masks.., you can get pan amd zoom that would be impossible even in helicopter. you can make 3D space ships fly behind hills and buildings.., its a technique but it takes ingenuity to do it on the cheap. if you want to do this.., theres no easy way.., unless graphics apps come easy to you.., its a stepp learning curve.., but what is important is to correct colour levels so that composited images dont look like cut outs