         }
     }
     
+    private let defaultOnImageName      = "SwitchBackground_on";
+    private let defaultOffImageName     = "SwitchBackground_off";
+    private let defaultThumbImageName   = "SwitchThumb";
+    private let defaultImageType        = "png";
+    
     // MARK: - @IBInspectable properties
     @IBInspectable public var onImage: UIImage?;
     @IBInspectable public var offImage: UIImage?;

        
        // Thumb Image
        if thumbImage == nil {
            let imageStr = NSBundle(forClass: DZCheckBox.self).pathForResource("SwitchThumb", ofType: "png");
            self.thumbImageView.image = UIImage(data: NSData(contentsOfURL: NSURL(fileURLWithPath: imageStr!))!);
        }
        else {

        
        // On Image
        if onImage == nil {
            let imageStr = NSBundle(forClass: DZCheckBox.self).pathForResource(defaultOnImageName, ofType: defaultImageType);
            self.onImageView.image = UIImage(data: NSData(contentsOfURL: NSURL(fileURLWithPath: imageStr!))!);
            
        }
