Change your links to:
<a href="#" class="icon"><img src="images/fb.jpg" alt="" /></a>
And your jQuery to:
$(document).ready(function () {
$("a img").on('mouseover', function () {
$(this).animate({
top: '-125px'
});
});
});
Be sure to wrap this jQuery in a document ready handler OR place it at the end of the page.