el-upload上传图片居中显示不变形

             <div style="border:1px solid #dcdfe6;width:220px;height:160px;display: flex;justify-content: center; align-items: center;">
                  <span v-if="imageUrl" class="avatar"  style="display:block;width:210px;height:150px; ">
                       <img :src="imageUrl" style="width: 100%;height: 100%; object-fit: scale-down;">
                  </span>
              </div>
              <el-upload action="" :before-upload="beforeSealUpload" :http-request="uploadSealImg" style="position: absolute;top:0;width: 300px;left:225px">
                <span style="font-size: 14px;color: #4A90E2;cursor: pointer;">上传图片</span>
              </el-upload>

 uploadSealImg(param){
      // let formData=new FormData();
      // formData.append('file',param