if (document) {
	img1on = new Image();      
	img1on.src = "../images/photo_back_sbt.gif";
	img2on = new Image();      
	img2on.src = "../images/photo_next_sbt.gif";

	img1off = new Image(); 
	img1off.src = "../images/photo_back_bt.gif";
	img2off = new Image(); 
	img2off.src = "../images/photo_next_bt.gif";
}

// Function to 'activate' images
function imgOn(imgName) {
	if (document) {
		document[imgName].src = eval(imgName + "on.src");
	}
}

// Function to 'deactivate' images
function imgOff(imgName) {
	if (document) {
		document[imgName].src = eval(imgName + "off.src");
	}
}