Doc: update component document && examples

docs/examples-docs/image-preview.md

@@ -11,7 +11,7 @@ import { ImagePreview } from 'packages/index';
 
 export default {
   methods: {
-    handleImagePreview() {
+    showImagePreview() {
       ImagePreview([
         'https://img.yzcdn.cn/upload_files/2017/03/15/FkubrzN7AgGwLlTeb1E89-T_ZjBg.png',
         'https://img.yzcdn.cn/upload_files/2017/03/14/FmTPs0SeyQaAOSK1rRe1sL8RcwSY.jpeg',
@@ -38,22 +38,20 @@ import { ImagePreview } from 'vant';
 
 :::demo 基础用法
 ```html
-<van-button @click="handleImagePreview">预览图片</van-button>
-
-<script>
-import { ImagePreview } from 'packages/index';
+<van-button @click="showImagePreview">预览图片</van-button>
+```
 
+```javascript
 export default {
   methods: {
-    handleImagePreview() {
+    showImagePreview() {
       ImagePreview([
-        'https://img.yzcdn.cn/upload_files/2017/03/14/FmTPs0SeyQaAOSK1rRe1sL8RcwSY.jpeg',
-        'https://img.yzcdn.cn/upload_files/2017/03/15/FvexrWlG_WxtCE9Omo5l27n_mAG_.jpeg'
+        'https://img.yzcdn.cn/1.jpg',
+        'https://img.yzcdn.cn/2.jpg'
       ]);
     }
   }
 };
-</script>
 ```
 :::