To change the zoom factor:
Click in the image to increase the zoom factor and show more detail.
Click in the image to decrease the zoom factor and show less detail.
Adjusts the zoom so that the image fits inside the window.
Move the image inside the window.
To zoom into a specific area: click a starting point and then move the mouse to drag the rectangle over the area of interest.
Zooming only magnifies the image on your screen; it does not change the physical size of the picture.