Masking Elements
The huge advantage of masks is that the selected sections of an image do not have to be erased. The original is preserved under the masks. Due to this, maskings are often used to create several color variations of the same object. With the aid of masking paths, products or particular elements of an image can be recoloured. Moreover, professional image editors use masks for cropping and montage since you can integrate image content into the masked area of another picture.
For more information, have a look at Masking.