.test{background:url(/img/sun.png); display:block; width:50px; height:50px;}
.test:hover{background:url(/img/sol.png);}
.test2{background:url(/img/sunsol.png) no-repeat; display:block; width:50px; height:50px;}
.test2:hover{background-position: 0 -50px;}
.test3{border: 2px solid blue; background:url(/img/sunsol.png) no-repeat; display:block; width:54px; height:100px; padding:0; padding-top: 50px; background-position:2px 52px;}
.test3:hover{background-position: 2px 2px;}