1. 设背景图div一定要指定宽高，否则图片不显示
width:100%;
height:900px;
2. 缩小拉大窗口时背景图片也跟着缩放
background-image: url('../../images/home/bg_01.png');
background-position: center;
background-repeat: no-repeat;
3. 背景图不重复：
background-repeat:no-repeat
4. 背景图位置：
background:url(../image/header.jpg) no-repeat right bottom; /*相当于100% 100%*/
参考链接
5. react中加入背景图：
style={{background: `url(${i.imgUrl})`}}
6.背景图随着窗口缩小也全部撑满：
background: url(../styles/images/bg-2.png);
background-position: top center;
background-size: cover;
background-origin:border-box;
background-repeat:no-repeat;
background-attachment: scroll;
