element-plus/docs/examples/image/placeholder.vue

<template>
  <div class="demo-image__placeholder">
    <div class="block">
      <span class="demonstration">Default</span>
      <el-image :src="src"></el-image>
    </div>
    <div class="block">
      <span class="demonstration">Custom</span>
      <el-image :src="src">
        <template #placeholder>
          <div class="image-slot">Loading<span class="dot">...</span></div>
        </template>
      </el-image>
    </div>
  </div>
</template>

<script lang="ts">
import { defineComponent, ref } from 'vue'

export default defineComponent({
  setup() {
    const src = ref(
      'https://cube.elemecdn.com/6/94/4d3ea53c084bad6931a56d5158a48jpeg.jpeg'
    )

    return {
      src,
    }
  },
})
</script>