When dealing with computer graphics, layering is stacking various images, graphics, or text on top of one another. Layering in programs allows users to make alterations without changing the original image. It may also be toggled on or off, so the user may view how an image would look with or without layers.
The image shows what the Layers box looks like in Adobe Photoshop. Four visible layers can be moved above or below the others or hidden to affect the overall look of the final image.
Once an image containing layers is completed, it may be "flattened," combining them into a single layer. This option is often found in the "Layer" tab at the top of the screen.