To make your link image change when you scroll over it with your cursor:

If you look at my premium MFC account profile you'll see that I have a image that links to my amazon wishlist that looks like this,



but when you scroll over it, it changes to this,




What you want to do is add this css code in the "customize profile" section:
(note: I highlighted the parts in red that you need to change if you want to change the link and the images)

.amazonlink{
     width: 500px;
     height:166px;
     display:block;
     background:transparent     url('http://25.media.tumblr.com/143165aafabe89068970153c6a0de7ef/tumblr_mqojnoBvEl1rjl0hwo2_500.jpg') center top no-repeat;
}
.amazonlink:hover {
   background-image:url('http://24.media.tumblr.com/65e9059f9021a11b7177b532881223cd/tumblr_mqojnoBvEl1rjl0hwo1_500.jpg');
}


Then you want to add this html code in the "edit profile" section where ever you want your images to appear on your profile,
(note: the part highlighted in red is where you want to paste your link instead)


'amazonlink' title='amazonlink'>