home_off          = new Image();
  home_off.src      = "assets/images/home_off.gif";
	home_on           = new Image();
	home_on.src       = "assets/images/home_on.gif";
  bedroom_off       = new Image();
  bedroom_off.src   = "assets/images/bedroom_off.gif";
	bedroom_on        = new Image();
	bedroom_on.src    = "assets/images/bedroom_on.gif";  
	
	function change_it(ImgField,imgName) {		
	    document.images[ImgField].src = eval(imgName + ".src	");
	}