var preloaded = [];

	for (var i = 1; i <= 5; i++)
	 {
		preloaded[i] = [loadImage(i + "-0.gif"), loadImage(i + "-1.gif")];
		}

		function init() {
			// whatever stuff you need to do onload goes here.

			if (mtDropDown.isSupported()) {
				mtDropDown.initialize();
				menu1.onactivate = function() { swapImage("button1", preloaded[1][1].src) };
				menu1.ondeactivate = function() { swapImage("button1", preloaded[1][1].src) };

				menu1.onactivate = function() { swapImage("button2", preloaded[2][1].src) };
				menu1.ondeactivate = function() { swapImage("button2", preloaded[2][1].src) };

				menu1.onactivate = function() { swapImage("button3", preloaded[3][1].src) };
				menu1.ondeactivate = function() { swapImage("button3", preloaded[3][1].src) };

				menu1.onactivate = function() { swapImage("button4", preloaded[4][1].src) };
				menu1.ondeactivate = function() { swapImage("button4", preloaded[4][1].src) };

				menu1.onactivate = function() { swapImage("button5", preloaded[5][1].src) };
				menu1.ondeactivate = function() { swapImage("button5", preloaded[5][1].src) };
			}
		}

		// this is a crappy example preloader. Use whichever one you want.
		function loadImage(sFilename) {
			var img = new Image();
			img.src ="images/" + sFilename;
			return img;
		}

		// this is a crappy example image swapper. Use whichever you want.
		function swapImage(imgName, sFilename) {
		document.images[imgName].src = sFilename;
		}