Cropping allows you to isolate the portion of the image you want and discard the rest.
To crop an image, first click on the Crop Button 
on the Wizard Panel. A cropping
frame will appear on your image. Drag the frame with your mouse, or stretch
and shrink it using the adjustment handles, until it encloses the part of the
photo you want to keep. The gray area
outside the frame will be discarded.
Original image
Resize the cropping frame around the area you want to keep
Once your selection is in place, hit the Crop Image
button to crop it.
Cropped image
You can also crop your photo to a standard shape, such as 3x5 or 5x7, etc. To learn how, see Cropping to Standard Shapes in the chapter on Touching Up Photos.