Generally, in any picture viewing software, the scrolling option is always to the right of the screen. If you see the extreme right side of the screen, you will see a vertical bar with a different coloured bar in it. If you click on this bar and drag up or down, your picture will scroll up and down. If you have a scroller on your mouse, you can simply use that to scroll up and down. If there is no scroll option in the software that you are using, you can use the zoom and then go up and down with the help of the mouse.
