I was recently commissioned to do a product shoot a set of radiator guards at a school in Brighton. Most of them were white against white backgrounds, which don't really stand out. The exception was this one, against green glazed bricks. But the radiator, and the floor below, were sloping, which would not look right on the customer's website or brochure.  This video shows how to use Photoshop to solve this issue using lens correction, geometric correction, and transforming tools (skew, scale etc) in the Edit menu. The photo below shows the original and final images.

Transforming and resizing images in Photoshop