html

<div id="carousel-example-generic" class="carousel slide" data-ride="carousel">
        <!-- 指示器 -->
        <ol class="carousel-indicators">
          <li data-target="#carousel-example-generic" data-slide-to="0" class="active"></li>
          <li data-target="#carousel-example-generic
 
" data-slide-to="1"></li>
          <li data-target="#carousel-example-generic" data-slide-to="2"></li>
        </ol>
        <!-- 輪播圖片及說明文字 -->
        <div class="carousel-inner" role="listbox">
          <div class="item active">
            <a href="#
 
" class="pc_imgBox hidden-xs" style="background-image: url('images/2-1.png')"></a>
            <a href="#" class="m_imgBox hidden-lg hidden-md hidden-sm"><img src="images/1-1.png" alt=""></a>
          </div>
          <div class="item">
            <a href="#" class
 
="pc_imgBox hidden-xs" style="background-image: url('images/2-2.png')"></a>
            <a href="#" class="m_imgBox hidden-lg hidden-md hidden-sm"><img src="images/1-2.png" alt=""></a>
          </div>
          <div class="item">
            <a href="#" class="pc_imgBox hidden-xs" style="background-image: url('images/2-3.png')"></a>
            <a href="#" class="m_imgBox hidden-lg hidden-md hidden-sm"><img src="images/1-3.png" alt=""></a>
          </div>
        </div>
        <!-- 控制按鈕：左右切換 -->
        <a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">
          <span class="glyphicon glyphicon-chevron-left"></span>
        </a>
        <a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">
          <span class="glyphicon glyphicon-chevron-right"></span>
        </a>
      </div>

css

 .pc_imgBox{
            display: block;
            height: 400px;
            width: 100%;
            background-size: cover;
            background-position:  center;
            background-repeat: no-repeat;
        }
        .m_imgBox{
            display: block;
            width: 100%;
        }
        .carousel-indicators{
            background: #ccc;
        }

原文https://www.cnblogs.com/cui-ting/p/10837833.html