The Background property gets access to the layer's background object. The Background object holds pictures to be shown on the layer's background. The Layer's background can display unlimited graphics of different sizes and positions. For instance, the Picture property of the Background specifies the picture to be shown on the layer's background. Use the ExtraPicture property to assign a new picture on the same location. The Color property indicates the layer's color object, so you can apply a solid color on the layer's background.

The following screen shot shows pictures on each layer's background: