Eraser Tool
This tool is useful for erasing parts of the image. Note, however, that it works by marking areas of a layer as being transparent. This may result in a checkerboard pattern being shown. This pattern is simply used to indicate areas of the image that are transparent -- it is not actually part of the image.
Eraser Tool
This tool is also useful while working with multiple layers. If you have portions of a layer below that you want to show through to the top layers, you can use the eraser tool on those top layers.
Note
MS Paint's eraser tool works by painting with white. If this is the behavior that you want, we recommend that you use the Paintbrush tool and select white as the color to draw within the Colors Window.
Example
Original Image
After using the Eraser Tool in the middle of the image