async Task UpdateImageSource()
        {
            CleanImageSource();
            _softwareBitmap = _bitmap.ToSoftwareBitmap();
            _sbs            = new SoftwareBitmapSource();
            await _sbs.SetBitmapAsync(_softwareBitmap);

            image.Source = _sbs;

            imageGrid.Width  = _bitmap.PixelWidth;
            imageGrid.Height = _bitmap.PixelHeight;

            InitSelection();
        }