
This frame displays an image, which can be zoomed in or out with 
	  the slider at the frame's bottom. Buttons - and + or key 
      equivalents alt- and alt+ can be used to step the zoom in or 
	  out.
	  Dragging the mouse allows, when applicable, to draw a rectangle, to 
	  resize or move it around. Depending on the tool used, the 
	  rectangle can be a fixed size square.