update readme

Author: liyong03

README.md

@@ -3,11 +3,23 @@ YLGIFImage
 
 Asynchronized GIF image class and Image viewer supporting play/stop GIF images. 
 
-It just use very less memory. Following GIF usually will cost almost 1GB memory if it is fully decoded, but using YLGIFImage, it just use about 30MB memory.
+It just use very less memory. Following GIF usually will cost almost 600MB memory if it is fully decoded (800x600x389x4 Bytes), but using YLGIFImage, it just use about 30MB memory.
 
-![Joy](./YLGIFImageDemo/YLGIFImageDemo/joy.gif "Joy")
+->![Joy](./YLGIFImageDemo/YLGIFImageDemo/joy.gif =320x240)<-
 
+For this gif file, iOS Pinterest also will crash, but using YLGIFImage, it won't!
+
+####Using it
+For using YLGIFImage, it's very simple:
+
+    YLImageView* imageView = [[YLImageView alloc] initWithFrame:CGRectMake(0, 160, 320, 240)];
+    [self.view addSubview:imageView];
+    imageView.image = [YLGIFImage imageNamed:@"joy.gif"];
+
+Here is the demo looks like:
+
+->![Screenshot](./screenshot.png =320x568)<-
 
 Thanks
 ==========
-Thanks to [OLImageView](https://github.com/ondalabs/OLImageView)! I referred a lot to this project.
+Thanks to [OLImageView](https://github.com/ondalabs/OLImageView)! I referred a lot to this project, especially using NSDisplay.

YLGIFImageDemo/YLGIFImageDemo.xcodeproj/xcuserdata/liyong03.xcuserdatad/xcdebugger/Breakpoints_v2.xcbkptlist

@@ -30,7 +30,9 @@ - (void)viewDidLoad
     [super viewDidLoad];
     // Do any additional setup after loading the view.
 
-    YLImageView* imageView = [[YLImageView alloc] initWithFrame:CGRectMake(0, 50, 320, 240)];
+    self.title = @"YLGIFImageDemo";
+    
+    YLImageView* imageView = [[YLImageView alloc] initWithFrame:CGRectMake(0, 160, 320, 240)];
     [self.view addSubview:imageView];
     imageView.image = [YLGIFImage imageNamed:@"joy.gif"];
 }

YLGIFImageDemo/YLGIFImageDemo.xcodeproj/xcuserdata/liyong03.xcuserdatad/xcschemes/YLGIFImageDemo.xcscheme

@@ -16,7 +16,8 @@ - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(
     self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
     // Override point for customization after application launch.
     self.window.backgroundColor = [UIColor whiteColor];
-    self.window.rootViewController = [[DemoViewController alloc] init];
+    UINavigationController* navi = [[UINavigationController alloc] initWithRootViewController:[[DemoViewController alloc] init]];
+    self.window.rootViewController = navi;
     [self.window makeKeyAndVisible];
     return YES;
 }