download-file.wxml

<import src="../../../common/head.wxml" />
<import src="../../../common/foot.wxml" />

<view class="container">
  <template is="head" data="{{title: 'downloadFile'}}"/>

  <view class="page-body">
    <image wx:if="{{imageSrc}}" src="{{imageSrc}}" mode="center" />
    <block wx:else>
      <view class="page-body-wording">
        <text class="page-body-text">
          点击按钮下载服务端示例图片
        </text>
      </view>
      <view class="btn-area">
        <button bindtap="downloadImage" type="primary">下载</button>
      </view>
    </block>
  </view>

  <template is="foot" />
</view>