Simple CSS for hover image to enlarge

[Joe]

I have a very simple css (below) to enlarge an image when hover over but it doesn't work when I try to use it with web2py view like this: src="{{=URL('static','images/pic1.jpg')}}. Is there a way to make this work somehow or the only way to do this in web2py is by using java script?

<a class="thumb" href="#"><img src="images/pic1.jpg" alt=""><span><img src="images/pic2.jpg" style="width:500px" alt=""></span></a>

<style>
.thumb span {
    position:absolute;
    visibility:hidden;
}
.thumb:hover, .thumb:hover span {
    visibility:visible;
    top:100px; left:450px;
    z-index:1;
}