diff --git a/SDWebImage/SDWebImageManager.h b/SDWebImage/SDWebImageManager.h
index 8750730..9848999 100644
--- a/SDWebImage/SDWebImageManager.h
+++ b/SDWebImage/SDWebImageManager.h
@@ -181,6 +181,12 @@ SDWebImageManager *manager = [SDWebImageManager sharedManager];
  */
 + (SDWebImageManager *)sharedManager;
 
+/**
+ * Allows to specify instance of cache and image downloader used with image manager.
+ * @return new instance of `SDWebImageManager` with specified cache and downloader.
+ */
+- (instancetype)initWithCache:(SDImageCache *)cache downloader:(SDWebImageDownloader *)downloader;
+
 /**
  * Downloads the image at the given URL if not present in cache or return the cached version otherwise.
  *
diff --git a/SDWebImage/SDWebImageManager.m b/SDWebImage/SDWebImageManager.m
index 91475c1..a905e93 100644
--- a/SDWebImage/SDWebImageManager.m
+++ b/SDWebImage/SDWebImageManager.m
@@ -37,20 +37,22 @@
     return instance;
 }
 
-- (id)init {
+- (instancetype)init {
+    SDImageCache *cache = [SDImageCache sharedImageCache];
+    SDWebImageDownloader *downloader = [SDWebImageDownloader sharedDownloader];
+    return [self initWithCache:cache downloader:downloader];
+}
+
+- (instancetype)initWithCache:(SDImageCache *)cache downloader:(SDWebImageDownloader *)downloader {
     if ((self = [super init])) {
-        _imageCache = [self createCache];
-        _imageDownloader = [SDWebImageDownloader sharedDownloader];
+        _imageCache = cache;
+        _imageDownloader = downloader;
         _failedURLs = [NSMutableSet new];
         _runningOperations = [NSMutableArray new];
     }
     return self;
 }
 
-- (SDImageCache *)createCache {
-    return [SDImageCache sharedImageCache];
-}
-
 - (NSString *)cacheKeyForURL:(NSURL *)url {
     if (self.cacheKeyFilter) {
         return self.cacheKeyFilter(url);