diff --git a/SDWebImage/SDWebImageDownloader.m b/SDWebImage/SDWebImageDownloader.m
index 1c008d0..326a452 100644
--- a/SDWebImage/SDWebImageDownloader.m
+++ b/SDWebImage/SDWebImageDownloader.m
@@ -10,9 +10,6 @@
 #import "SDWebImageDownloaderOperation.h"
 #import <ImageIO/ImageIO.h>
 
-NSString *const SDWebImageDownloadStartNotification = @"SDWebImageDownloadStartNotification";
-NSString *const SDWebImageDownloadStopNotification = @"SDWebImageDownloadStopNotification";
-
 static NSString *const kProgressCallbackKey = @"progress";
 static NSString *const kCompletedCallbackKey = @"completed";
 
diff --git a/SDWebImage/SDWebImageDownloaderOperation.h b/SDWebImage/SDWebImageDownloaderOperation.h
index 21a3106..1b4beec 100644
--- a/SDWebImage/SDWebImageDownloaderOperation.h
+++ b/SDWebImage/SDWebImageDownloaderOperation.h
@@ -10,6 +10,11 @@
 #import "SDWebImageDownloader.h"
 #import "SDWebImageOperation.h"
 
+extern NSString *const SDWebImageDownloadStartNotification;
+extern NSString *const SDWebImageDownloadReceiveResponseNotification;
+extern NSString *const SDWebImageDownloadStopNotification;
+extern NSString *const SDWebImageDownloadFinishNotification;
+
 @interface SDWebImageDownloaderOperation : NSOperation <SDWebImageOperation>
 
 /**
@@ -36,6 +41,16 @@
  */
 @property (assign, nonatomic, readonly) SDWebImageDownloaderOptions options;
 
+/**
+ * The expected size of data.
+ */
+@property (assign, nonatomic) NSInteger expectedSize;
+
+/**
+ * The response returned by the operation's connection.
+ */
+@property (strong, nonatomic) NSURLResponse *response;
+
 /**
  *  Initializes a `SDWebImageDownloaderOperation` object
  *
diff --git a/SDWebImage/SDWebImageDownloaderOperation.m b/SDWebImage/SDWebImageDownloaderOperation.m
index e7bafc9..7308d2b 100644
--- a/SDWebImage/SDWebImageDownloaderOperation.m
+++ b/SDWebImage/SDWebImageDownloaderOperation.m
@@ -12,6 +12,11 @@
 #import <ImageIO/ImageIO.h>
 #import "SDWebImageManager.h"
 
+NSString *const SDWebImageDownloadStartNotification = @"SDWebImageDownloadStartNotification";
+NSString *const SDWebImageDownloadReseiveResponseNotification = @"SDWebImageDownloadReseiveResponseNotification";
+NSString *const SDWebImageDownloadStopNotification = @"SDWebImageDownloadStopNotification";
+NSString *const SDWebImageDownloadFinishNotification = @"SDWebImageDownloadFinishNotification";
+
 @interface SDWebImageDownloaderOperation () <NSURLConnectionDataDelegate>
 
 @property (copy, nonatomic) SDWebImageDownloaderProgressBlock progressBlock;
@@ -20,7 +25,6 @@
 
 @property (assign, nonatomic, getter = isExecuting) BOOL executing;
 @property (assign, nonatomic, getter = isFinished) BOOL finished;
-@property (assign, nonatomic) NSInteger expectedSize;
 @property (strong, nonatomic) NSMutableData *imageData;
 @property (strong, nonatomic) NSURLConnection *connection;
 @property (strong, atomic) NSThread *thread;
@@ -209,6 +213,10 @@
         }
 
         self.imageData = [[NSMutableData alloc] initWithCapacity:expected];
+        self.response = response;
+        dispatch_async(dispatch_get_main_queue(), ^{
+            [[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadResponseNotification object:self];
+        });
     }
     else {
         NSUInteger code = [((NSHTTPURLResponse *)response) statusCode];
@@ -221,7 +229,7 @@
             [self.connection cancel];
         }
         dispatch_async(dispatch_get_main_queue(), ^{
-            [[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadStopNotification object:nil];
+            [[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadStopNotification object:self];
         });
 
         if (self.completedBlock) {
@@ -346,7 +354,8 @@
         self.thread = nil;
         self.connection = nil;
         dispatch_async(dispatch_get_main_queue(), ^{
-            [[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadStopNotification object:nil];
+            [[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadStopNotification object:self];
+            [[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadFinishNotification object:self];
         });
     }
     
@@ -385,7 +394,7 @@
         self.thread = nil;
         self.connection = nil;
         dispatch_async(dispatch_get_main_queue(), ^{
-            [[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadStopNotification object:nil];
+            [[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadStopNotification object:self];
         });
     }