<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style type="text/css" rel="stylesheet">
*{margin: 0;padding: 0;}
html{
height: 100%
}
body{
height: 100%;
background: url(wallpaper.jpg) no-repeat;
background-size: 100% 100%;
}
</style>
</head>
<body>
</body>
</html>
图片全屏显示代码-css3
原文：https://www.cnblogs.com/qikeyishu/p/9099617.html
