asp.Netアップロード画像保存サムネイル画像透かし

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        string filename = FileUpload1.FileName;
        string nowpath = Server.MapPath(".") + "\\";
        filename = nowpath + filename;

        //    
        FileUpload1.SaveAs(filename);

        System.Drawing.Image image, newimage, syimage;
        System.Drawing.Image.GetThumbnailImageAbort callb = null;
        image = System.Drawing.Image.FromFile(filename);
        syimage = System.Drawing.Image.FromFile(Server.MapPath(".") + "\\" + "   .gif");//       "   .gif"  ,       ：http://www.baidu.com/img/baidu.gif

        //     
        newimage = image.GetThumbnailImage(100, 100, callb, new IntPtr());
        newimage.Save(filename + ".   .png");
        newimage.Dispose();

        //     
        Graphics g = Graphics.FromImage(image);
        Font f = new Font("  ", 16);
        Brush b = new SolidBrush(ColorTranslator.FromHtml("#FF0000"));
        string addText = "      ";
        g.DrawString(addText, f, b, 10, 10);
        g.DrawImageUnscaled(syimage, 50, 50);
        //g.DrawImage(newimage,50,50,100,100);
        g.Dispose();

        //     
        image.Save(filename + ".  .png");

        image.Dispose();
        syimage.Dispose();

        Image1.ImageUrl = FileUpload1.FileName;
        Image2.ImageUrl = FileUpload1.FileName + ".   .png";
        Image3.ImageUrl = FileUpload1.FileName + ".  .png";

    }
}