private void UpdateScreenshotType_(ScreenshotTypeEnum?screenshotType, Bitmap image)
        {
            if (screenshotType.HasValue)
            {
                logger_.Verbose("given {0} already have the value '{1}'. using it.", nameof(screenshotType), screenshotType.Value);
                screenshotType_ = screenshotType.Value;
                return;
            }

            Size viewportSize = driver_.GetDefaultContentViewportSize();

            if (image.Width <= viewportSize.Width && image.Height <= viewportSize.Height)
            {
                screenshotType_ = ScreenshotTypeEnum.VIEWPORT;
            }
            else
            {
                screenshotType_ = ScreenshotTypeEnum.ENTIRE_FRAME;
            }
            logger_.Verbose("updated screenshot type to {0}", screenshotType_);
        }