Place your pointer inside the picture but not close to the centre.
You will see your pointer turn into the move icon
To move in a given direction,
hold down your left mouse button and slowly move it in the direction you want
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 centre of the picture.
Zoom-out icon is available in the lower centre 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