How to expand image size of button when mouse moves over it

Hi guys !!

i would just like to now how you could expand an image when the mouse moves over it.
I’m trying to copy this effect:http://sportsgirl.com.au/
as you can see, not only does the image increase in size, but it also shrinks the other buttons around it when the mouse goes over it. How could i do this too?
your help will be sooo much appreciated!!
thankyou! xx