diff --git a/SKPhotoBrowser/SKCache.swift b/SKPhotoBrowser/SKCache.swift
index d2974b1..79f25bf 100644
--- a/SKPhotoBrowser/SKCache.swift
+++ b/SKPhotoBrowser/SKCache.swift
@@ -18,19 +18,19 @@ public class SKCache {
     }
 
     public func imageForKey(key: String) -> UIImage? {
-        return (self.imageCache as! SKImageCacheable).imageForKey(key)
+        return (self.imageCache as? SKImageCacheable)!.imageForKey(key)
     }
 
     public func setImage(image: UIImage, forKey key: String) {
-        (self.imageCache as! SKImageCacheable).setImage(image, forKey: key)
+        (self.imageCache as? SKImageCacheable)!.setImage(image, forKey: key)
     }
 
     public func removeImageForKey(key: String) {
-        (self.imageCache as! SKImageCacheable).removeImageForKey(key)
+        (self.imageCache as? SKImageCacheable)!.removeImageForKey(key)
     }
 
     public func imageForRequest(request: NSURLRequest) -> UIImage? {
-        if let response = (self.imageCache as! SKRequestResponseCacheable).cachedResponseForRequest(request) {
+        if let response = (self.imageCache as? SKRequestResponseCacheable)!.cachedResponseForRequest(request) {
             let data = response.data
 
             return UIImage(data: data)
@@ -41,7 +41,7 @@ public class SKCache {
 
     public func setImageData(data: NSData, response: NSURLResponse, request: NSURLRequest) {
         let cachedResponse = NSCachedURLResponse(response: response, data: data)
-        (self.imageCache as! SKRequestResponseCacheable).storeCachedResponse(cachedResponse, forRequest: request)
+        (self.imageCache as? SKRequestResponseCacheable)!.storeCachedResponse(cachedResponse, forRequest: request)
     }
 }
 
diff --git a/SKPhotoBrowser/SKZoomingScrollView.swift b/SKPhotoBrowser/SKZoomingScrollView.swift
index 63a08c8..3e8547c 100644
--- a/SKPhotoBrowser/SKZoomingScrollView.swift
+++ b/SKPhotoBrowser/SKZoomingScrollView.swift
@@ -191,7 +191,9 @@ public class SKZoomingScrollView: UIScrollView, UIScrollViewDelegate, SKDetectin
         contentSize = CGSize.zero
         
         if !flag {
-            indicatorView.startAnimating()
+            if photo.underlyingImage == nil {
+                indicatorView.startAnimating()
+            }
             photo.loadUnderlyingImageAndNotify()
         } else {
             indicatorView.stopAnimating()
diff --git a/SKPhotoBrowserTests/SKCacheTests.swift b/SKPhotoBrowserTests/SKCacheTests.swift
index 6213089..5dc5fae 100644
--- a/SKPhotoBrowserTests/SKCacheTests.swift
+++ b/SKPhotoBrowserTests/SKCacheTests.swift
@@ -35,7 +35,7 @@ class SKCacheTests: XCTestCase {
 
     func testDefaultCacheImageForKey() {
         // given
-        let cache = (self.cache.imageCache as! SKDefaultImageCache).cache
+        let cache = (self.cache.imageCache as? SKDefaultImageCache)!.cache
         cache.setObject(self.image, forKey: self.key)
 
         // when
@@ -50,14 +50,14 @@ class SKCacheTests: XCTestCase {
         self.cache.setImage(self.image, forKey: self.key)
 
         // then
-        let cache = (self.cache.imageCache as! SKDefaultImageCache).cache
+        let cache = (self.cache.imageCache as? SKDefaultImageCache)!.cache
         let cachedImage = cache.objectForKey(self.key) as? UIImage
         XCTAssertNotNil(cachedImage)
     }
 
     func testDefaultCacheRemoveImageForKey() {
         // given
-        let cache = (self.cache.imageCache as! SKDefaultImageCache).cache
+        let cache = (self.cache.imageCache as? SKDefaultImageCache)!.cache
         cache.setObject(self.image, forKey: self.key)
 
         // when