The pixel brush tool allows you to draw on the screen a pixel accurate stroke. This is the perfect tool if you are trying to create an icon image. The current Stroke Color will be the color of the drawn path.
The Brush Size option allows you to specify how wide of a stroke is drawn.
You can either draw or erase an existing pixel in the canvas by toggling the Draw and Erase buttons found in the Pixel Brush Options panel
The widget for pixel brush elements allows you to modify the selected pixels in an existing stroke.Pixel selection
You can select drawn pixel by clicking it. You can also select multiple pixels by pressing Ctrl key and clicking each pixels you want to select.