AppDelegate.swift

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    // Override point for customization after application launch.
    
    let duration = 2.0
    
    let launchScreen = UIStoryboard(name: "LaunchScreen", bundle: nil)
    let launchViewController = launchScreen.instantiateInitialViewController()
    let imageView = launchViewController?.view.viewWithTag(100) as! UIImageView
    imageView.image = UIImage.animatedImageNamed("win_", duration: duration)
    self.window?.rootViewController = launchViewController
    
    let delay = duration * Double(NSEC_PER_SEC)
    let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))
    dispatch_after(time, dispatch_get_main_queue()) {
        let mainScreen = UIStoryboard(name: "Main", bundle: nil)
        let mainViewController = mainScreen.instantiateInitialViewController()
        self.window?.rootViewController = mainViewController
    }
    
    return true
}