左上角图片不见了
<! DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>吉米的书</title>
<style type="text/css">
.content{border:4px solid #badbdb;
padding:34px 15px 15px;}
.book{background-image:url(t_book.gif) no-repeat;}
img{
width:80px;
height:80px;
margin:10px 18px;
border: 1px solid #b1adad;}
</style>
</head>
<body>
<div class="content book">
<img src="book1.jpg" alt="book1" />
<img src="book2.jpg" alt="book2" />
<img src="book3.jpg" alt="book3" />
<img src="book4.jpg" alt="book4" />
<img src="book5.jpg" alt="book5" />
<img src="book6.jpg" alt="book6" />
</body>
</div>
</html>
问题在哪呢?