只需要为添加效果的图片定义一个伪类
img.zoom-img:hover {
-webkit-transform: scale(1.15);
-webkit-transition-timing-function: ease-out;
-webkit-transition-duration: 20000ms;
-moz-transform: scale(1.15);
-moz-transition-timing-function: ease-out;
-moz-transition-duration: 750ms;
overflow: hidden;
}