试一试 - CSS background-size

<!DOCTYPE html>
<html>
<head>
<style>
.div1 {
   border: 1px solid black;
   height:150px;
   width:180px;
   background:url(img_flwr.gif);
   background-repeat: no-repeat;
}

.div2 {
   border: 1px solid black;
   height:150px;
   width:180px;
   background:url(img_flwr.gif);
   background-repeat: no-repeat;
   background-size: contain;
}

.div3 {
   border: 1px solid black;
   height:150px;
   width:180px;
   background:url(img_flwr.gif);
   background-repeat: no-repeat;
   background-size: cover;
}
</style>
</head>
<body>

<p>Original image:</p>
<div class="div1">
<p>Lorem ipsum dolor sit amet.</p>
</div>

<p>Using the "contain" keyword:</p>
<div class="div2">
<p>Lorem ipsum dolor sit amet.</p>
</div>

<p>Using the "cover" keyword:</p>
<div class="div3">
<p>Lorem ipsum dolor sit amet.</p>
</div>

</body>
</html>