img.checkbox {
	cursor: pointer;
	vertical-align:middle;
	width : 22px;
	height : 20px;
	border : none;
	margin: 0;padding:0;
	background-color:transparent;
	background-repeat:no-repeat;
	background-size:18px 18px;
	
	background-image : url('../img/todo-unchecked.png');
}
img.checkbox.checked {
	background-image : url('../img/todo-checked.png');
}