Photo retouches work well when a building is existing and you are going to make changes to part of it. Additions, new entrances, color changes, etc. can be illustrated onto the photograph as if your project is already completed. Either you provide a well focused digital photo or you describe the view you want and I take the photo with my digital SLR camera. That becomes the “Before” photo. You also provide plans/drawings/info for the new design. Then i get a large print made and work directly on it to show the “After”. It is especially effective to show the “Before” and “After” photos in your presentation.