 
     /// If the cached image is insufficient for the current frame
     fileprivate func cacheIsDirty() -> Bool {
-        guard let image = image.image else { return true }
+        guard let image = imageView.image else { return true }
         
         if cachedSampleRange.count == 0 {
             return true

                let status = self.asset!.statusOfValue(forKey: "duration", error: &error)
                switch status {
                case .loaded:
                    self.image.image = nil
                    self.highlightedImage.image = nil
                    self.progressSamples = 0
                    self.zoomStartSamples = 0

    }

    /// View for rendered waveform
    fileprivate let imageView: UIImageView = {
        let retval = UIImageView(frame: CGRect.zero)
        retval.contentMode = .scaleToFill
        return retval
