body {font-size:16px;}

#size .li1 a {background-position:0 0; width:32px;}
#size .li2 a {background-position:-32px 0; width:36px;}
#size .li3 a {background-position:-68px -82px; width:33px;}

#size .li1 a:hover {background-position:0 -41px; width:32px;}
#size .li2 a:hover {background-position:-32px -41px; width:36px;}
#size .li3 a:hover {background-position:-68px -82px; width:33px;}