These are the three views of an image. The main view is heavily zoomed – which turns on the pixel grid. It does not make sense to have a pixel grid in the main view otherwise. The main view has an area selected for the ‘Pixels’ window. The big difference between the two is that the main view is aliased – so edges are blended. The Pixels view is not aliased so each pixel cell is always a distinct color. So the main view is better for painting on while the Pixels view is better for simply selecting a color for a selected pixel. The third view is the Panner. The Panner has a small rectangle (over the boats outboard motor) which indicates the location and size of the main view on the full image. This rectangle can be dragged about to scroll the main view.
