<div class="dog"></div>

.dog {
    width: 5.4rem;                     \\图片宽度
    height: 3.04rem;                   \\图片高度
    background-image: url(head.jpg);
    background-size: 5.4rem 3.04rem;   \\图片宽高
    background-position: -5.4rem 0;
    animation: run 2s linear infinite;
}

@keyframes run {
    from {background-position: -5.4rem 0;}
    to {background-position: 0 0;}
}

$(document).ready(function(){
  remReSize();
  setTimeout(function() {
    $('.dog').css('animation', 'run 2s linear infinite');
  }, 0);
});