var preloadFlag = false;

function newImage(arg) {
  if (document.images) {
    rslt = new Image();
    rslt.src = arg;
    return rslt;
  }
}

function preloadImages() {
  if (document.images && (preloadFlag == false)) {  // main nav preload
    btn1_0 = newImage("images/btn1_0.jpg");
    btn1_1 = newImage("images/btn1_1.jpg");
    btn2_0 = newImage("images/btn2_0.jpg");
    btn2_1 = newImage("images/btn2_1.jpg");
    //...
    preloadFlag = true;
  }
 	window.status = "Osborne Bay Resort · a care free lifestyle residential resort on beautiful Banks Lake, Washington";
}

function btn_over(imgName) {  // main nav
  if (document.images && (preloadFlag == true)) {
		document[imgName].src = eval(imgName + "_1.src");
	} 
}

function btn_off(imgName) {
  if (document.images) {
    document[imgName].src = eval(imgName + "_0.src");
	}
}