To start:
Place your pointer inside the picture.
You will see your pointer
turn into the move icon
To move in a given direction,
set your pointer just outside the middle of the picture, hold
down your left mouse button and slowly move it in the direction you want to
travel.
When you place your pointer in the very middle of the screen,
it changes to one of 2 other icons:
Zoom-in
icon 
is available in the upper center of the picture.
Zoom-out
icon 
is available in the lower center of the picture. To activate, move your pointer
until it changes to one of these icons and press and hold your left mouse button.
As you zoom-in the picture gets a little grainy. This is normal and if you zoom-out
the clarity will be restored