 //MARK: Public data methods
 extension DTPhotoViewerController {
     // Update data before calling theses methods
-    public func insertPhotos(_ at: [Int], completion: ((Bool) -> Void)?) {
-        let indexPaths = indexPathsForIndexes(indexes: at)
+    open func reloadData() {
+        collectionView.reloadData()
+    }
+    
+    open func insertPhotos(at indexes: [Int], completion: ((Bool) -> Void)?) {
+        let indexPaths = indexPathsForIndexes(indexes: indexes)
         
         collectionView.performBatchUpdates({ 
             self.collectionView.insertItems(at: indexPaths)
         }, completion: completion)
     }
     
-    public func deletePhotos(_ at: [Int], completion: ((Bool) -> Void)?) {
-        let indexPaths = indexPathsForIndexes(indexes: at)
+    open func deletePhotos(at indexes: [Int], completion: ((Bool) -> Void)?) {
+        let indexPaths = indexPathsForIndexes(indexes: indexes)
         
         collectionView.performBatchUpdates({
             self.collectionView.deleteItems(at: indexPaths)
         }, completion: completion)
+    }
+    
+    open func reloadPhotos(at indexes: [Int]) {
+        let indexPaths = indexPathsForIndexes(indexes: indexes)
+        
+        collectionView.reloadItems(at: indexPaths)
+    }
+    
+    open func movePhoto(at index: Int, to newIndex: Int) {
+        let indexPath = IndexPath(item: index, section: 0)
+        let newIndexPath = IndexPath(item: newIndex, section: 0)
+        
+        collectionView.moveItem(at: indexPath, to: newIndexPath)
+    }
+    
+    open func scrollToPhoto(at index: Int, animated: Bool) {
+        if self.collectionView.numberOfItems(inSection: 0) > index {
+            let indexPath = IndexPath(item: index, section: 0)
+            collectionView.scrollToItem(at: indexPath, at: UICollectionViewScrollPosition.right, animated: animated)
+        }
     }
     
     // Helper for indexpaths

            let size = image.size
            var destinationSize = CGSize.zero
            
            if image.size.height/image.size.width > view.frame.size.width/view.frame.size.height {
                destinationSize.width = view.frame.size.width
                destinationSize.height = view.frame.size.width * (size.height / size.width)
            }


//MARK: UICollectionViewDataSource
extension DTPhotoViewerController: UICollectionViewDataSource {
    //MARK: Public methods
    public var currentPhotoIndex: Int {
        return Int(scrollView.contentOffset.x / scrollView.frame.width)
    }
    
    public var currentPhotoZoomScale: CGFloat {
        let index = currentPhotoIndex
        let indexPath = IndexPath(item: index, section: 0)
        
        if let cell = collectionView.cellForItem(at: indexPath) as? DTPhotoCollectionViewCell {
            return cell.scrollView.zoomScale
        }
        
        return 1.0
    }
    
    public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return dataSource?.numberOfItems(in: self) ?? 1
    }
