diff --git a/SDWebImage/Core/SDWebImageDownloaderOperation.m b/SDWebImage/Core/SDWebImageDownloaderOperation.m
index 1de8212a..00d803f2 100644
--- a/SDWebImage/Core/SDWebImageDownloaderOperation.m
+++ b/SDWebImage/Core/SDWebImageDownloaderOperation.m
@@ -208,8 +208,13 @@ typedef NSMutableDictionary<NSString *, id> SDCallbacksDictionary;
     if (self.dataTask) {
         if (self.options & SDWebImageDownloaderHighPriority) {
             self.dataTask.priority = NSURLSessionTaskPriorityHigh;
+            self.coderQueue.qualityOfService = NSQualityOfServiceUserInteractive;
         } else if (self.options & SDWebImageDownloaderLowPriority) {
             self.dataTask.priority = NSURLSessionTaskPriorityLow;
+            self.coderQueue.qualityOfService = NSQualityOfServiceBackground;
+        } else {
+            self.dataTask.priority = NSURLSessionTaskPriorityDefault;
+            self.coderQueue.qualityOfService = NSQualityOfServiceDefault;
         }
         [self.dataTask resume];
         for (SDWebImageDownloaderProgressBlock progressBlock in [self callbacksForKey:kProgressCallbackKey]) {