Hi all!

I got a problem with my website and I can't figure it out, maybe one of you can help me out:

Please visit: http://test.thierryemmery.nl/about.html
On this page I have a photo, when you move/hover your mouse over it it changes the photo to another one. Under the photo there is a button called " Thierry als werknemer?" I am trying to make the photo change when you hover over the blue button with your mouse.

I have no idea how to make this happen. Anyone can help me out? Thanks in a advance!