The viewing options available depend on which layout view you are using.
Click on an image slice and drag it with the mouse pointer:
Drag the mouse pointer through a slice, up or down.
You can also click on an image slice and scroll with the mouse wheel.
Drag the mouse pointer:
You can also click on an image slice and zoom by simultaneously holding down the Ctrl button and scrolling up or down with the mouse wheel.
|Rotate a 3D view|
Click on a 3D image and drag the mouse pointer.
Click on an image slice and drag the mouse pointer to improve the visibility of structure contrast: