2D Graphics C#

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Net;
using System.IO;
public class Form1 : System.Windows.Forms.Form {
    [STAThread]
    static void Main() {
        Application.Run(new Form1());
    }
    protected override void OnPaint(System.Windows.Forms.PaintEventArgs e) {
        string p = "s.JPG";
        Image i = Image.FromFile(p);
        Image tn = i.GetThumbnailImage(50, 50, null, IntPtr.Zero);  // <=>(IntPtr)0
        e.Graphics.DrawImage(tn, 100, 0, tn.Width, tn.Height);
        e.Graphics.Dispose();
    }
}