Turn on Zoom tool in Tool Palette or use (Z).
Note on the three buttons on the zoom tool bar, 1:1, Fit to Screen, and Print Size. Try them and see what happens.
1:1 magnifies to image to 100%, enabling spotting and other fine manipulations.Fit to Screen does just that, and Print Size show you the image at the size it will print. Try holding the Alt key and pay careful attention to the zoom magnifying glass. Click with it and see what happens.
