.box-out { position:relative; width:65px; height:65px; } .wifi { width:65px; height:65px; position:absolute; border-radius:100%; left:0; top:0; background:url("http://www.jq22.com/tp/c7bab3d6-d1bf-41b6-91ad-b6539d46f46d.jpg") 0 3px no-repeat; animation:wifiEmit 2500ms infinite; } @keyframes wifiEmit { 25% { width:15px; height:15px; top:25px; background-position:0 -21px; } 50% { width:25px; height:25px; top:20px; background-position:0 -16px; } 75% { width:45px; height:45px; top:12px; background-position:0 -8px; } 100% { top:0; width:65px; width:65px; background-position:0 3px; } }