timer tick fire only one time dute to [Response.OutputStream] is optoin to relad page more than ontime

protected void Timer1_Tick(object sender, EventArgs e)
{
Bitmap bmp = new Bitmap(150, 400);
Graphics g = Graphics.FromImage(bmp);

Pen blackPen = new Pen(Color.Red);
y -= 100; ;
height += 50;
RectangleF drawRect0 = new RectangleF(x, y, width, height);
Pen blackPen0 = new Pen(Color.Red);
g.DrawRectangle(blackPen0, x, y, width, height);

g.FillRectangle(Brushes.Sienna, x, y, width, height);

// String path2 = Server.MapPath("~/Image/DrawRectangl.jpg");

// bmp.Save(path2, ImageFormat.Jpeg);
// Image1.ImageUrl = "~/Image/DrawRectangl.jpg";
if (height >= 520)
{
Response.Write("<h2>ERROR</h2>");
}

Response.ContentType = "image/jpeg";
//bmp.Save(Response.OutputStream, ImageFormat.Jpeg);
//Response.Redirect("~/cricle.aspx");
bmp.Save(Response.OutputStream, ImageFormat.Jpeg);
}