Get image from http

Hello,
I havn't program C# for a while, but now i am starting up again.
This code does work trough the compiler, but in real world it doesn't work, what's the problem?

Code:

#region using

using System;
using System.Drawing;
using System.Windows.Forms;
using System.IO;
using System.Net;

#endregion

public class MainsClass
{
	
	public static void Main()
	{
		
		new InterfaceClass();
		
	}
	
}

public class InterfaceClass
{
	public InterfaceClass()
	{
		Form MainWindow = new Form();
		PictureBox MainBox = new PictureBox();
				
		MainWindow.Text = "Startup Screen";
		MainWindow.StartPosition = FormStartPosition.CenterScreen;
		MainWindow.Width = 640;
		MainWindow.Height = 480;
		
		WebRequest reg = WebRequest.Create("http://raceoffice.segel.aland.fi:81/record/current.jpg");
		Stream stream = reg.GetResponse().GetResponseStream();
		
		Bitmap img = new Bitmap(stream);
		
		MainBox.BackgroundImage = img;
		MainBox.Width = 600;
		MainBox.Height = 450;
		MainBox.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
		
		MainBox.Visible = true;
		MainWindow.ShowDialog();
	}
}

Sorry about my bad english, i'm from finland (europe).

Thanks,
/Linus

You didn't connect your picturebox to your form in any way, so I guess your form shows up without a picture. But that's just a wild guess, it would really help if you specify "doesn't work" a bit.

Yep, the picturebox doesn't show up, i have tried to connect it, but i don't really know how to do it, after one hour at google and a lot of self thinking, i posted here.

How do i connect it to the form then?

MainWindow.Controls.Add(MainBox);

Thank You very much!
Now it work's brilliant.