c#给本地图片打文字水印

  #region 加图片水印
        /// <summary>
        /// 给图片打水印
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button4_Click(object sender, EventArgs e)
        {
            System.Drawing.Image image = System.Drawing.Image.FromFile("d://b.jpg");
            Graphics g = Graphics.FromImage(image);
            g.DrawImage(image, 0, 0, image.Width, image.Height);
            Font f = new Font("Verdana", 32);
            Brush b = new SolidBrush(Color.Red);
            g.DrawString("鼓舞飞扬", f, b, 10, 10);
            g.Dispose();

            string spath = "d://" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".jpg";
            image.Save(spath);
            image.Dispose();

            if (File.Exists("d://b.jpg"))
            {
                File.Delete("d://b.jpg");
            }

            MessageBox.Show("完成操作");

        }  
        #endregion