An image consists of a background upon which are placed various other objects. For example: A blue sky which then has clouds placed on it. Next a green hill is placed on the image followed by trees and then a house and barn. Finally, a few cows are added. Each of these placement events comprise a layer. As can be seen, an image can consist of numerous layers. Layers allow specific areas of an image to be edited without affecting any other data. Objects in one layer can be repositioned, edited, drawn, pasted, and removed without disturbing objects on other layers. In our example, for instance, we could change the clouds from cotton puff to thunder storm types without affecting any other aspect of the image.