把BitmapSource图片数据保存到文件

        /// <summary>
        /// 保存图片到文件
        /// </summary>
        /// <param name="image">图片数据</param>
        /// <param name="filePath">保存路径</param>
        private void SaveImageToFile(BitmapSource image, string filePath)
        {
            BitmapEncoder encoder = GetBitmapEncoder(filePath);
            encoder.Frames.Add(BitmapFrame.Create(image));

            using (var stream = new FileStream(filePath, FileMode.Create))
            {
                encoder.Save(stream);
            }
        }

        /// <summary>
        /// 根据文件扩展名获取图片编码器
        /// </summary>
        /// <param name="filePath">文件路径</param>
        /// <returns>图片编码器</returns>
        private BitmapEncoder GetBitmapEncoder(string filePath)
        {
            var extName = Path.GetExtension(filePath).ToLower();
            if (extName.Equals(".png"))
            {
                return new PngBitmapEncoder();
            }
            else
            {
                return new JpegBitmapEncoder();
            }
        }

        /// <summary>
        /// 保存图片菜单点击事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void menuSaveImage_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                if (imageData == null)
                {
                    return;
                }

                var dlg = new Microsoft.Win32.SaveFileDialog();
                dlg.Filter = "PNG图片(*.png)|*.png|JPEG图片(*.jpg)|*.jpg|所有文件(*.*)|*.*";
                var rst = dlg.ShowDialog();
                if (rst == true)
                {
                    var fileName = dlg.FileName;

                    SaveImageToFile(imageData, fileName);
                    MessageBox.Show("保存成功");
                }
            }
            catch (Exception ex)
            {
                logger.Error(ex);
                MessageBox.Show(ex.Message);
            }
        }