c#添加水印效果【1】

下面的代码中 添加文字水印 和 图片水印是不能共存的（下面写在一起是为了方便显示）

private void Btn_Upload_Click(object sender, System.EventArgs e)        {            if(UploadFile.PostedFile.FileName.Trim()!="")            {                //上传文件                string extension = Path.GetExtension(UploadFile.PostedFile.FileName).ToUpper();                string fileName = DateTime.Now.Year.ToString() + DateTime.Now.Month.ToString() + DateTime.Now.Day.ToString() + DateTime.Now.Hour.ToString() + DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString();                string path = Server.MapPath(".") + "/UploadFile/" + fileName + extension;                UploadFile.PostedFile.SaveAs(path);                //加文字水印，注意，这里的代码和以下加图片水印的代码不能共存                System.Drawing.Image image = System.Drawing.Image.FromFile(path);                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.White);                string addText = AddText.Value.Trim();                g.DrawString(addText, f, b, 10, 10);                g.Dispose();                //加图片水印                System.Drawing.Image image = System.Drawing.Image.FromFile(path);                System.Drawing.Image copyImage = System.Drawing.Image.FromFile( Server.MapPath(".") + "/Alex.gif");                Graphics g = Graphics.FromImage(image);                g.DrawImage(copyImage, new Rectangle(image.Width-copyImage.Width, image.Height-copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);                g.Dispose();                //保存加水印过后的图片,删除原始图片                string newPath = Server.MapPath(".") + "/UploadFile/" + fileName + "_new" + extension;                image.Save(newPath);                image.Dispose();                if(File.Exists(path))                {                    File.Delete(path);                }                Response.Redirect(newPath);            }        }