How to add text on a image?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.Drawing.Text;
public partial class Default3 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
    string image = Server.MapPath("Message - Popup - prohp_net.jpg");
    Bitmap bitmapimage = new System.Drawing.Bitmap(image);
        Graphics graphicimage = Graphics.FromImage(bitmapimage);
        graphicimage.SmoothingMode = SmoothingMode.AntiAlias;
        graphicimage.DrawString("That's my boy!", new Font("Arial", 12, FontStyle.Bold),SystemBrushes.WindowText,new Point(100,250));
        Response.ContentType = "image/jpg";
        bitmapimage.Save(Response.OutputStream, ImageFormat.Jpeg);
    }
}