Here is the original, a photo of Cathy Bell. I chose this image because it maximizes the amount of body replacement needed which seemed appropriate for a invisibles example.Well begin by using the clone tool and start removing her face, hair and the shadow shes casting on the vent. On a new layer, making sure the use all layers box is checked, clone portions of the available vent over the areas you need to remove. I like to use a smallish brush, varying between a hard and soft tip. That makes it easier to get clean edges around items youre keeping, such as the hat. You could also duplicate areas of the vent on another layer and place them into position. A little bit of touch up with a brush is usually required to fix anything that doesnt perfectly line up with the cloning. If I get cloning artifacts I remove them by spot retouching the area with a click instead of a stroke, from a similar area of color, density and texture.