css3中让图像居中可以使用哪个元素

<div class="container container-2">
    <img src="http://scrm-staging-cdn.oss-cn-hangzhou.aliyuncs.com/avatar/wechat/aHR0cDovL3d4LnFsb2dvLmNuL21tb3Blbi9YeFQ5VGlhSjFpYmYzdFk4b2hENHFpYmxkTUdEbk1NRXFuZVdlZk5pY2lic1h1MjFZdHAxV1o2bGsxUTFVeE9vSzY4QVJEa0tRZ05OYWgzeTFzY01YUUp3clBRLzA=">
</div>

.container-2 {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex-box;
    display: flex;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -webkit-box-pack:center;
    -ms-flex-pack:center;
    justify-content:center;
    text-align: center;
}

<h3 class="demo">绝对定位+Margin</h3>
<div class="container container-1">
    <img src="http://scrm-staging-cdn.oss-cn-hangzhou.aliyuncs.com/avatar/wechat/aHR0cDovL3d4LnFsb2dvLmNuL21tb3Blbi9YeFQ5VGlhSjFpYmYzdFk4b2hENHFpYmxkTUdEbk1NRXFuZVdlZk5pY2lic1h1MjFZdHAxV1o2bGsxUTFVeE9vSzY4QVJEa0tRZ05OYWgzeTFzY01YUUp3clBRLzA=">
</div>

.container-1 {position: relative;}

.container-1 img{position: absolute; top: 0; bottom: 0; left: 0; right: 0; margin: auto;}