实现图片宽度100%填充外层，高度自适应

.btbox{display: flex;position:absolute;top: 67%;width: 70%;margin-left: 15%;}

<view class="btbox">
    <image src="../../images/mercer/sh.jpg" mode="widthFix" >image>
    <image src="../../images/mercer/sr.jpg" mode="widthFix">image>
  view>