var restore, resobj=-1;

function swapImgRestore() {
  if ((resobj>-1)&&(restore.src)) {
  	document.images[resobj].src=restore.src;
  }
}

function swapImage(imgobj, bla, imgsrc, blub) {
  if(document.images){ 
    var x=0;
	restore = new Image();
	while ((document.images[x])&&(document.images[x].name!=imgobj)) {
		x++;
	}
	if ((document.images[x])&&(document.images[x].name==imgobj)) {
		restore.src=document.images[x].src;
		resobj=x;
		document.images[x].src=imgsrc;
	} else {
		resobj=-1;
	}
  }
}