获得没有设置宽度或高度的div的背景图像的理想大小

I have the following Markup:

我有以下标记:

<div class="jumbotron jumbotron-personal-user clearfix">
     <div class="container">
          <div class="row">
               <div class="col-lg-1 col-centered">
                    <img src="img/avatar04.png" class="profile-avatar">
               </div>
          </div>
      </div>
</div>
<div