app 页面 图片高度与宽度一致，撑满宽度

.food-img
      position relative
      width 100%
      height 0
      padding-top 100%
      img
       position absolute
       top 0
       left 0
       width 100%
       height 100%

<div class="food-img">
        <img src="../../assets/food1.jpg"/>
      </div>