<style>
.max_box {
width: 200px;
margin: auto;
}
.box {
width: 100%;
height: 0;
padding-top: 100%;
position: relative;
}
img {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%
}
</style>
</head>
<body>
<div class="max_box">
<div class="box">
<img src="01.jpg">
</div>
</div>
</body>
