div 背景自适应

.bg {
            background: url(images/title_bg.jpg);
            filter: "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale')";
            -moz-background-size: 100% 100%;
            background-size: 100% 100%;
            height: 150px;
        }

<div class="bg">
      <img src="data:images/temp.png" style="width: 100px; height: 100px; border-radius: 50%; margin-top: 30px; margin-left: 20px" alt="头像" />
 </div>