I can also do a Lasso selection which allows me to basically draw an area. You can do up here a Rectangular or Elliptical selection. So it is not probably one I want to use but if you have something where the color really stands out then that might be the ideal tool for you. I can select another area of the shirt, like that, and you can see I am not really that successful in grabbing everything. So you can see it is selecting my shirt there and it is not quite getting all of it. With the instant alpha tool you can grab a color and you can select it. The first way probably won't work really well for this image is to use this instant alpha tool. I'm going to go to the Tools here and turn that on. Using Preview version 7 I'm going to show you how to cut out part of an image, like somebody from an image, and perhaps paste it somewhere else.
Let me show you how you can cut out objects from images in Preview. Check out Cutting Out Part Of an Image With Preview at YouTube for closed captioning and more options.