var on = 1;
var off = 0;
var ImgArray = new Array();
ImgArray["blogButton"] = new Array();
ImgArray["blogButton"][on] = new Image(); 
ImgArray["blogButton"][on].src  = "img/blog_anim.gif";
ImgArray["blogButton"][off] = new Image();
ImgArray["blogButton"][off].src  = "img/blog.gif";
ImgArray["contactButton"] = new Array();
ImgArray["contactButton"][on] = new Image(); 
ImgArray["contactButton"][on].src  = "img/contact_anim.gif";
ImgArray["contactButton"][off] = new Image();
ImgArray["contactButton"][off].src  = "img/contact.gif";

function over(which) {
  document.images[which].src = ImgArray[which][on].src;
}
function out(which) {
  document.images[which].src = ImgArray[which][off].src;
}