Replace image placeholder links with local image addresses

src/views/post/components/PostSetting.vue

@@ -153,7 +153,7 @@
             <div class="post-thumb">
               <img
                 class="img"
-                :src="selectedPost.thumbnail || '//i.loli.net/2019/05/05/5ccf007c0a01d.png'"
+                :src="selectedPost.thumbnail || '/placeholder.png'"
                 @click="()=>this.thumbDrawerVisible=true"
               >
               <a-button

src/views/sheet/components/SheetSetting.vue

@@ -73,7 +73,7 @@
             <div class="sheet-thumb">
               <img
                 class="img"
-                :src="selectedSheet.thumbnail || '//i.loli.net/2019/05/05/5ccf007c0a01d.png'"
+                :src="selectedSheet.thumbnail || '/placeholder.png'"
                 @click="()=>this.thumbDrawerVisible = true"
               >
               <a-button

src/views/sheet/internal/PhotoList.vue

@@ -129,7 +129,7 @@
           >
             <div class="photo-detail-img">
               <img
-                :src="photo.url || '//i.loli.net/2019/05/05/5ccf007c0a01d.png'"
+                :src="photo.url || '/placeholder.png'"
                 @click="showThumbDrawer"
               >
             </div>