using css to change size of the icon Options

[Maccabee]

basically I have an image that is a link and It is 128x128 pixels. But it has been changed to 100x100 using html. What I want is the image to then change to probably 120 or 128 pixels when I hover it. Also if there is any javascript to make it a smooth trnasition that would be great. Heres what I tried but did not work.

CSS:

CODE

a.iconlink:link, a.iconlink:active, a.iconlink:visited{
margin-top:-30px;
width:100px;
height:100px;
}

a.iconlink:hover{
margin-top:-30px;
width:120px;
height:120px;
}

HTML

CODE

<a class="iconlink" href="#"><img class="iconlink" style="margin-top:-40px;" border="0" height="100" width="100" src="contact.png"></a>

I was suprised that it didnt work. I wasn't sure if I was supposed to put the class in the image or the link. Also when I tried putting the style on the image into the css page(because I use as little html as possible) it doesn't work. I'm sure there is something obvious I didnt think of but troubleshotting didn't work.