css图片触碰放大

<div class="imgdev">
            <img src="http://www.touyinghudong.com/tpl/www/images/box7-3.jpg"/>
 </div>

　　div

.imgdev {
    width: 300px;
    height: 92.84px;
    margin: 0 auto;
    overflow: hidden;
}
img {
    max-width: 100%;
    max-height: 100%;
    transition: all 0.6s;
}
img:hover {
    transform: scale(1.2);
}

　　css样式