var map = new GMap2(document.getElementById("map_canvas"));
map.setCenter(new GLatLng(40.740, -74.18), 12); 
// ground overlay 
  
var boundaries = new GLatLngBounds(new GLatLng(40.716216,-74.213393), new GLatLng(40.765641,-74.139235)); 
var oldmap = new GGroundOverlay("http://www.lib.utexas.edu/maps/historical/newark_nj_1922.jpg", boundaries); 
map.addControl(new GSmallMapControl()); 
map.addControl(new GMapTypeControl()); 
map.addOverlay(oldmap);