Refresh previews on data change

src/components/Folder.vue

@@ -41,6 +41,18 @@ export default {
         }
     },
     mounted() {
+        this.refreshPreviews();
+    },
+    watch: {
+        data: {
+            handler() {
+                this.refreshPreviews();
+            },
+        },
+    },
+    methods: {
+        /** Refresh previews */
+        refreshPreviews() {
             if (!this.data.previewFileInfos) {
                 const folderPath = this.data.path.split('/').slice(3).join('/');
                 dav.getFolderPreviewFileIds(folderPath, 4).then(fileInfos => {
@@ -52,13 +64,13 @@ export default {
                     this.previewFileInfos = fileInfos;
                 }).catch(() => {
                     this.data.previewFileInfos = [];
+                    this.previewFileInfos = [];
                 });
             } else {
                 this.previewFileInfos = this.data.previewFileInfos;
             }
         },
 
-    methods: {
         /** Open album folder */
         openFolder(id) {
             this.$router.push({ name: 'albums', params: { id } });