在mounted中通过接口得到images数据，并赋值给el-upload中的file-list，为什么图片不显示？

<el-upload :action="cdn"
  :file-list="images"
  :before-upload="beforeUpload"
  :on-preview="onPreview"
  :on-remove="(file, fileList) => onRemove(fileList, 'detail')"
  :on-success="(response, file, fileList) => onSuccess(response, 'detail')"
  :data="{entity: 'product'}"
  list-type="picture-card" multiple>
  <i class="el-icon-plus"></i>
</el-upload>