.cherep a {
 font: bold 28px Verdana, Arial, sans-serif;
 text-decoration: none;
 text-align: center;
  
 background: url('http://vselennia.ucoz.ru/cherep5.jpg');
 display: block;
 width: 50px;
 line-height: 70px;
 height: 70px;
 border-radius: 5px; 
}

.cherep a:hover{
 background-position: 0px -69px;
 text-decoration: none;
 
 border-radius: 5px;
}