function simpleTristate(selector, offImgUrl, onImgUrl, hoverImgUrl) {
	// Default off image
	$(selector).css("background-image","url('"+offImgUrl+"')");
	// Hover
	$(selector).hover(function(){
		$(this).css("background-image","url('"+hoverImgUrl+"')");
	}, function() {
		if ($(this).attr("alt")=="0") {
			$(this).css("background-image","url('"+offImgUrl+"')");
		} else {
			$(this).css("background-image","url('"+onImgUrl+"')");
		}
	});
	// Click
	$(selector).click(function(){
		if ($(this).attr("alt")=="0") {
			$(this).attr("alt","1");
			$(this).css("background-image","url('"+onImgUrl+"')");
		} else {
			$(this).attr("alt","0");
			$(this).css("background-image","url('"+offImgUrl+"')");
		}
	});	
}