jquery ui datepicker button image on hover

Hi experts,

I'm using the jquery ui datepicker.

I have an example that uses an icon trigger similar to this example:
http://jqueryui.com/datepicker/#icon-trigger

This is my fiddle for my example

http://jsfiddle.net/dcxd61vw/

I have 2 calendar image icons i'm using.

I have a blue calendar icon that looks like this:
This is the url to the image: https://farm6.staticflickr.com/5703/21213071831_2337f61ccd_o.png



I have a green calendar icon that looks like this:
This is the url to the image: https://farm1.staticflickr.com/756/20584041683_7e6c1fcf6d_o.png


So right now in my fiddle above when my page launches the blue calendar icon is displayed.

But what I want is when I hover my mouse cursor over the calendar icon it should switch to use the green calendar icon.

Anyone know how to set a on hover image for the buttonimage of the datepicker?