To Create Captcha Images using .net ( Cs File )

Onload Function
CaptchaImage ci = new CaptchaImage(this.Session["CaptchaImageText"].ToString(), 200, 50, "Century Schoolbook");

// Change the response headers to output a JPEG image.
this.Response.Clear();
this.Response.ContentType = "image/jpeg";

// Write the image to the response stream in JPEG format.
ci.Image.Save(this.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
//imgCaptcha.ImageUrl = ci;
// Dispose of the CAPTCHA image object.
ci.Dispose();