<el-upload
  class="upload-demo"
  action="//jsonplaceholder.typicode.com/posts/"
  :on-preview="handlePreview"
  :on-remove="handleRemove"
  :file-list="fileList">
  <el-button size="small" type="primary">点击上传</el-button>
  <p slot="tip" class="el-upload__tip">只能上传jpg/png文件，且不超过500kb</p>
</el-upload>
<script>
  export default {
    data() {
      return {
        fileList: [{name: 'food.jpeg', url: 'https://fuss10.elemecdn.com/3/63/4e7f3a15429bfda99bce42a18cdd1jpeg.jpeg?imageMogr2/thumbnail/360x360/format/webp/quality/100'}, {name: 'food2.jpeg', url: 'https://fuss10.elemecdn.com/3/63/4e7f3a15429bfda99bce42a18cdd1jpeg.jpeg?imageMogr2/thumbnail/360x360/format/webp/quality/100'}]
      };
    },
    methods: {
      handleRemove(file, fileList) {
        console.log(file, fileList);
      },
      handlePreview(file) {
        console.log(file);
      }
    }
  }
</script>

Use the code from the official website directly, and then use the background interface to accept and process files. Will it be ok soon?