function changeImage(targetImg1, newImg1) {
  if (document[targetImg1]) {
    document[targetImg1].src = eval(newImg1 + ".src");
  }
}

// Pre-load graphics
home_on = new Image(); home_on.src = "images/buttons/home.gif";
home_off = new Image(); home_off.src = "images/buttons/home-g.gif";
strollers_on = new Image(); strollers_on.src = "images/buttons/strollers.gif";
strollers_off = new Image(); strollers_off.src = "images/buttons/strollers-g.gif";
orderinginfo_on = new Image(); orderinginfo_on.src = "images/buttons/orderinginfo.gif";
orderinginfo_off = new Image(); orderinginfo_off.src = "images/buttons/orderinginfo-g.gif";
about_on = new Image(); about_on.src = "images/buttons/aboutus.gif";
about_off = new Image(); about_off.src = "images/buttons/aboutus-g.gif";
circleoffriends_on = new Image(); circleoffriends_on.src = "images/buttons/circleoffriends.gif";
circleoffriends_off = new Image(); circleoffriends_off.src = "images/buttons/circleoffriends-g.gif";
volunteers_on = new Image(); volunteers_on.src = "images/buttons/volunteers.gif";
volunteers_off = new Image(); volunteers_off.src = "images/buttons/volunteers-g.gif";
donate_on = new Image(); donate_on.src = "images/buttons/donate.gif";
donate_off = new Image(); donate_off.src = "images/buttons/donate-g.gif";
contactus_on = new Image(); contactus_on.src = "images/buttons/contactus.gif";
contactus_off = new Image(); contactus_off.src = "images/buttons/contactus-g.gif";
group_on = new Image(); group_on.src = "images/buttons/supportgroup.gif";
group_off = new Image(); group_off.src = "images/buttons/supportgroup-g.gif";
chefchallenge_on = new Image(); chefchallenge_on.src = "images/buttons/chefchallenge-on.gif";
chefchallenge_off = new Image(); chefchallenge_off.src = "images/buttons/chefchallenge.gif";