$(document).ready(function() {
    $('#id_product_type').change(function() {
        if ( $("#id_product_type").val() != '') {
            $("img#genericPicture").attr({src : "/media/images/headwalls/generic-"+$("#id_product_type").val()+".gif"});
            $("img#genericPicture").show();
            $.get('/products/addtosession/?openheadwallpic='+ '/media/images/headwalls/generic-'+ $("#id_product_type").val()+".gif");
        }
    });
});