
In Photoshop, press D on your keyboard to give you the default background colors (black and white). The X key will toggle which is the background and which is the foreground.
- Set your background color the match your photo.
- Select the crop tool and drag it across the full size of your photo.
- Grab the edges of your crop frame and drag them out to the size you want.
- Hit Enter on your keyboard and the background color will be filled in.
The photo above was taken against a 6' x 7' Lastolite Hilight background with white vinyl on the floor in a small living room.