var imageBaseUrl = "http://www.patiodaddiobbq.com/images/";
var corners = new Array("corner1.gif",
                        "corner2.gif",
                        "corner3.gif",
                        "corner4.gif",
                        "corner5.gif",
                        "corner6.gif",
                        "corner7.gif");  

$(document).ready(function() {
  $("#headerCorner").attr("src", imageBaseUrl + corners[Math.round((Math.random()*6))]);  
});