var navifolder = "../images.two.state/";
    if (toplevel == 1) {    navifolder = "images.two.state/";    } 
    
    var twostatebuttonslo = new Array(twostateimages.length);
    var twostatebuttonshi = new Array(twostateimages.length);
    
    for (i = 0;  i < twostateimages.length;  i++) {
        twostatebuttonslo[twostateimages[i]] = new Image();
        twostatebuttonslo[twostateimages[i]].src = navifolder + twostateimages[i] + "lo.png";
        twostatebuttonshi[twostateimages[i]] = new Image();
        twostatebuttonshi[twostateimages[i]].src = navifolder + twostateimages[i] + "hi.png";
    }

    function singlebuttonhi(name) {
        document.images[name].src = twostatebuttonshi[name].src;
	      return true;
	  }
    function singlebuttonlo(name) {
        document.images[name].src = twostatebuttonslo[name].src;
	      return true;
	  }