@IBOutlet weak var monsterImg: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        var imgArray = [UIImage]()
        //init your image array, for example
        for var x = 1; x <= 4; x++ {
            let img = UIImage(named: "idle\(x).png")
            imgArray.append(img!)
        }

        monsterImg.animationImages = imgArray
        monsterImg.animationDuration = 0.8
        monsterImg.animationRepeatCount = 0
        monsterImg.startAnimating()

        //animationImages
        //An array of UIImage objects to use for an animation.

        //animationDuration
        //The amount of time it takes to go through one cycle of the images.
        //The time duration is measured in seconds. The default value of this property is equal to the number of images multiplied by 1/30th of a second. Thus, if you had 30 images, the value would be 1 second.

        //animationRepeatCount
        //Specifies the number of times to repeat the animation.
        //The default value is 0, which specifies to repeat the animation indefinitely.
    }