$(document).ready(function() {
$(".rollover").hover(
    function(){
        var extension = $(this).attr("src").match( /(\.[a-zA-Z]+)$/g );
        if($(this).attr("src").indexOf("-active") == -1) {
            var newSrc = $(this).attr("src").replace(extension,"-active" + extension );
            $(this).attr("src",newSrc);
        }
    },
    function(){
        var extension = $(this).attr("src").match( /(\.[a-zA-Z]+)$/g );
        if($(this).attr("src").indexOf("-active" + extension) != -1) {
            var oldSrc = $(this).attr("src").replace("-active" + extension, extension);
            $(this).attr("src",oldSrc);
        }
    }
);
});