This window allows you to manage the multiple layers that an image may contain in Paint.NET. There is always one active layer, and all drawing affects only that layer. Each layer may be given a name, and may have a blending mode and opacity set. You may also make a layer visible or invisible by setting the checkbox appropriately.
You may think of the layers of an image as representing a stack of transparency sheets placed one on top of the other. Images that are on lower layers will show through to the top, but only if the layers on top do not occlude them. For greater discussion about the concept of layers, please visit the Working with Layers section.
This will add a new, completely transparent layer to the image. It will have a generic name that indicates what layer position it has been placed at, such as "Layer 4."
This will delete the active layer from the image. You may not delete a layer if it is the only one in the image.
This will take the active layer, duplicate its contents and attributes, and place it in the image after the original layer.
This will take the current layer and merge (combine) it into the layer below it.
This will move the current layer to a higher position in the layer order.
This will move the current layer to a lower position in the layer order.
This will bring up the properties for the active layer. From here you may give the layer a different name, toggle its visibility, and set its blending properties.
For greater discussion about Blend Modes, please visit the Blend Modes section.