+    /**
+     * Reset the image zoom to default value for each CachedFragments
+     */
+    public void resetZoom() {
+        Iterator<FileFragment> entries = mCachedFragments.values().iterator();
+        while (entries.hasNext()) {
+        FileFragment fileFragment = (FileFragment) entries.next();
+            if (fileFragment instanceof PreviewImageFragment) {
+                ((PreviewImageFragment) fileFragment).getImageView().resetZoom();
+            }
+        }
+    }
+