A generic error occurred in GDI while generating Captcha in ASP.Net

Hi,

I am getting exception on server when saving chapcha image in forder

A generic error occurred in GDI+. But is is working fine in local server without any error.

Please help me.

my codes .

using (Bitmap bitmap = new Bitmap(106, 35))
                {

                    string imgCaptchaToSave = string.Empty;
                    string captchaText = Guid.NewGuid().ToString().Substring(0, 6);
                    ViewState["Captcha"] = captchaText.ToString();
                    using (Graphics graphics = Graphics.FromImage(bitmap))
                    {
                        Font font = new Font("Verdana", 25, FontStyle.Regular, GraphicsUnit.Pixel);
                        graphics.DrawString(captchaText, font, new SolidBrush(Color.FromArgb(255, 0, 0)), 0, 0);
                        imgCaptchaToSave = captchaText + ".jpg"; //Path.GetFileNameWithoutExtension(Path.GetRandomFileName()) + ".jpg";
                       // bitmap.Save(Server.MapPath("~/Images/Captcha/") + imgCaptchaToSave, ImageFormat.Jpeg);
                        using (var m = new MemoryStream())
                        {
                            bitmap.Save(m, ImageFormat.Jpeg);
                            var img = System.Drawing.Image.FromStream(m);
                            img.Save(Server.MapPath("~/Images/Captcha/") + imgCaptchaToSave);
                        }

                        imgCaptcha.ImageUrl = "~/Images/Captcha/" + imgCaptchaToSave;
                        imgCaptcha.Visible = true;
                        txtCaptchaText.Text = string.Empty;
                        graphics.Flush();
                        graphics.Dispose();
                        GC.Collect();
                    }
                }