"zoomable" interaction

I saw this on the bbc news website about the awful tornado in Moore - I really liked the idea of recreating this concept in Storyline but wasn't too sure about how to recreate the zoom and pan effect. 

http://www.bbc.co.uk/news/world-us-canada-22661624

I've had a play around and I think I've done an ok job of recreating some of the features but I'm sure the community can help make this smoother...my attempt uses quite a lot of slides and large images; I wonder whether it could be done with states or layers?

Here is a preview of my version:

https://dl.dropboxusercontent.com/u/108477689/ZoomTest/story.html

Cheers,

Greg