scroll image with mouse movement

[JoshuaFoster]

Like Flickr website viewer, it scrolls automatically the image only with the movement of cursor around the viewport. When cursor goes to top, scroll image to top, cursor left, image to left, and so on. I've made a simple webpage with pure javascript, to demostrate this feature.

EDIT(New updated hosting in github, hostinger was down)
http://mangared.github.io/viewermouse/

In the page I put some big images, when the first image is loaded, you move the cursor and the image scrolls, click it to change image, scroll up/down the mouse wheel and change zoom, same as key + and -, press 0 to restart zoom, the page preloads next image, the code to move the image is just 6 lines