drawing in Asp.Net

I want the image to be drawn on the my webpage(basically it is just a line which depends on some values). It seems that I am drawing something by this function, but it is just a small rectangle in the left upper corner of the page and nothing else is on the page. I think that the second problem has something to do with "stream.WriteTo(Response.OutputStream);" It outputs only the image and nothing else. The first problem I don't know what is wrong. Any suggestions, please!!!

The code:


//aspx.cs file

protected System.Web.UI.WebControls.Image tempImage;
const int panelW=100, panelH=30;

void build()
{
Panel1=new Panel1();
Panel1.Width=panelW;
Panel1.Height=panelH;
Panel1.BackColor=Color.SeaGreen;
tempImage=new System.Web.UI.WebControls.Image();
Panel1.Controls.Add(tempImage);
System.IO.MemoryStream stream = new System.IO.MemoryStream();

Bitmap image=new Bitmap((int) 10, (int)10);

Graphics g=Graphics.FromImage(image);
//g.Clear(Color.SeaGreen);
Brush brush=new SolidBrush(Color.Yellow);
g.FillRectangle(brush, 5,5,100,20);

image.Save(stream, System.Drawing.Imaging.ImageFormat.Gif);
stream.Position = 0;

stream.WriteTo(Response.OutputStream);
}