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

        function changeImages() {
	        if (document.images && (preloadFlag == true)) {
		        for (var i=0; i<changeImages.arguments.length; i+=2) {
			        document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		        }
	        }
        }

        var preloadFlag = false;
        function preloadImages() {
	        if (document.images) {
		        welkom_over = newImage("img/btn_welkom_over.jpg");
				tweedehands_over = newImage("img/tweedehands_over.jpg");
				ligging_over = newImage("img/ligging_over.jpg");
				
				modellen_over = newImage("img/modellen_over.jpg");
				naverkoop_over = newImage("img/naverkoop_over.jpg");
				contact_over = newImage("img/contact_over.jpg");
		        preloadFlag = true;
	        }
        }