diff --git a/docs/src/Preview.vue b/docs/src/Preview.vue
index 52b0e731..7e233b63 100644
--- a/docs/src/Preview.vue
+++ b/docs/src/Preview.vue
@@ -1,6 +1,6 @@
 <template>
   <div>
-    <img class="preview-image" :src="image">
+    <img :class="['preview-image', `preview-image--${imageName}`]" :src="image">
     <div class="preview-popup">
       <div class="preview-content">
         <img src="https://img.yzcdn.cn/vant-weapp/qrcode-201808101114.jpg">
@@ -13,15 +13,17 @@
 <script>
 const PREFIX = 'https://img.yzcdn.cn/vant-weapp/';
 const MAP = {
-  index: 'index-201904170551.png',
+  index: 'index-20190715.png',
   transition: 'transition-20180821.png'
 };
 
 export default {
   computed: {
+    imageName() {
+      return location.hash.slice(1);
+    },
     image() {
-      const hash = location.hash.slice(1);
-      return PREFIX + (MAP[hash] || MAP.index);
+      return PREFIX + (MAP[this.imageName] || MAP.index);
     }
   }
 };
@@ -42,7 +44,10 @@ body {
   &-image {
     width: 100%;
     display: block;
-    margin-top: -62px;
+
+    &--transition {
+      margin-top: -62px;
+    }
   }
 
   &-popup {