public override MonoTouch.UIKit.UIImage PhotoScrubberView (NIPhotoScrubberView photoScrubberView, int thumbnailIndex)
			{
				var photoIndexKey = _controller.CacheKeyForPhotoIndex (thumbnailIndex);

				var image = (UIImage)_controller.ThumbnailImageCache.ObjectWithName (photoIndexKey);
				if (image == null) {
					var photo = Photos [thumbnailIndex];
					_controller.RequestImageFromSource (photo.ThumbnailSoruce, NIPhotoScrollViewPhotoSize.NIPhotoScrollViewPhotoSizeThumbnail, thumbnailIndex);
				}

				return image;
			}
			public override int NumberOfPhotosInScrubberView (NIPhotoScrubberView photoScrubberView)
			{
				return Photos.Count;
			}