话不多说，代码如下
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>伸缩布局</title>
<style type="text/css">
*{
margin: 0;
padding:0;
-webkit-box-sizing: border-box;
box-sizing: border-box;
}
html,
body {
height: 100%;
}
p{
height: 100px;
width: 100px;
overflow: hidden;
display:flex;
border: 1px dotted red;
align-items: center;
justify-content:center;
}
img{
width: 50px;
height: 50px;
}
</style>
</head>
<body>
<p>
<img src=/uploadfile/2015/1109/20151109101218254.jpg" alt="" /></p>
</body>
</html>
则图片居中