Can't add an image using iTextReader and pdf attached to email is empty

See more:

ASP.NET

public void PDFGeneration()
        {
            var output = new MemoryStream();

            // Create a Document object
            var document = new Document();

            // Create a new PdfWriter object, specifying the output stream
            
            var writer = PdfWriter.GetInstance(document, output);

            // Open the Document for writing
            writer.CloseStream = false;
            document.Open();
            var titleFont = FontFactory.GetFont("Arial", 18, Font.BOLD);
            var subTitleFont = FontFactory.GetFont("Arial", 14, Font.BOLD);
            var boldTableFont = FontFactory.GetFont("Arial", 12, Font.BOLD);
            var endingMessageFont = FontFactory.GetFont("Arial", 10, Font.ITALIC);
            var bodyFont = FontFactory.GetFont("Arial", 12, Font.NORMAL);

            document.Add(new Paragraph("Hungry Bytes User Details", titleFont));
            var orderInfoTable = new PdfPTable(2);
            orderInfoTable.HorizontalAlignment = 0;
            orderInfoTable.SpacingBefore = 10;
            orderInfoTable.SpacingAfter = 10;
            orderInfoTable.DefaultCell.Border = 0;
            orderInfoTable.SetWidths(new int[] { 1, 4 });

            orderInfoTable.AddCell(new Phrase("Name:", boldTableFont));
            orderInfoTable.AddCell(txtName.Text);
            orderInfoTable.AddCell(new Phrase("Surname:", boldTableFont));
            orderInfoTable.AddCell(txtSurname.Text);
            orderInfoTable.AddCell(new Phrase("Gender:", boldTableFont));
            orderInfoTable.AddCell(GenderDropDownList.SelectedValue);
            orderInfoTable.AddCell(new Phrase("Address 1:", boldTableFont));
            orderInfoTable.AddCell(txtAddress1.Text);
            orderInfoTable.AddCell(new Phrase("Address 2:", boldTableFont));
            orderInfoTable.AddCell(txtAddress2.Text);
            orderInfoTable.AddCell(new Phrase("Country:", boldTableFont));
            orderInfoTable.AddCell(CountryDropDownList.SelectedItem.ToString());
            orderInfoTable.AddCell(new Phrase("Town:", boldTableFont));
            orderInfoTable.AddCell(TownDropDownList.SelectedItem.ToString());
            orderInfoTable.AddCell(new Phrase("Email Address:", boldTableFont));
            orderInfoTable.AddCell(txtEmail.Text);
            orderInfoTable.AddCell(new Phrase("Date of Birth:", boldTableFont));
            orderInfoTable.AddCell(txtDateOfBirth.Text);
            orderInfoTable.AddCell(new Phrase("Blood Group:", boldTableFont));
            orderInfoTable.AddCell(BloodGroupDropDownList.SelectedItem.ToString());
            orderInfoTable.AddCell(new Phrase("Contact Number:", boldTableFont));
            orderInfoTable.AddCell(txtContactNumber.Text);
            orderInfoTable.AddCell(new Phrase("Username:", boldTableFont));
            orderInfoTable.AddCell(txtUsername.Text);
            //orderInfoTable.AddCell(new Phrase("Picture:", boldTableFont));
            //orderInfoTable.AddCell(ProfilePicFileUpload);
            orderInfoTable.AddCell(new Phrase("Password:", boldTableFont));
            orderInfoTable.AddCell(txtPassword.Text);
            orderInfoTable.AddCell(new Phrase("Confirm Password:", boldTableFont));
            orderInfoTable.AddCell(txtConfirmPass.Text);

            //var logo = iTextSharp.text.Image.GetInstance(Server.MapPath("~/images/banner1.jpg"));
            //logo.SetAbsolutePosition(540, 800);
            //document.Add(logo);
            GeneratePDFwithImage();
            document.Add(orderInfoTable);

            document.Close();

            Response.ContentType = "application/pdf";
            Response.AddHeader("Content-Disposition", string.Format("attachment;filename=Receipt-{0}.pdf", txtUsername.Text));
            Response.BinaryWrite(output.ToArray());
            _sendMail(output);
        }

        private void _sendMail(Stream output) 
        {
            string FromMail = "hungrybytes061@gmail.com";
            string ToMail = txtEmail.Text;
            string Subject = "User Details PDF";
            string Body = "Your Registration Details";
            using (Attachment att = new Attachment(output, "UserDetails.pdf", MediaTypeNames.Application.Pdf))
            {
                using (MailMessage mm = new MailMessage(
                FromMail, ToMail, Subject, Body))
                {
                    mm.Attachments.Add(att);
                    SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
                    smtp.Credentials = new NetworkCredential("hungrybytes061", "hungrybytes061");
                    smtp.EnableSsl = true;
                    smtp.Send(mm);
                }
            }
        }

        protected void GeneratePDFwithImage()
        {
            string path = Server.MapPath("~/images/");
            string fileName = "pdfDocument" + DateTime.Now.Ticks + ".pdf";
            Document doc = new Document();
            try
            {
                PdfWriter.GetInstance(doc, new FileStream(path + fileName, FileMode.Create));
                doc.Open();

                // Add the image now
                iTextSharp.text.Image jpg = iTextSharp.text.Image.GetInstance(Server.MapPath("~/images/banner1.jpg"));
                doc.Add(jpg);
            }
            catch (Exception ex)
            {
                lblMessage.Text = ex.ToString();
            }
            finally
            {
                doc.Close();
            }
        }

Hi, I have tried different methods in order to add an image/logo to the pdf using ITextSharp and have failed doing so. In one of the methods I stated the coordinates where the image should be but I don't really know how coordinates work exactly and the image would not be positioned in the desired position. The other method I used didn't return any image at all.
Also when a new user registers to my website, an email is sent with user details via pdf but the generated pdf is empty when attached to the email.
I would really appreciate some help in this pls.

Thanks in advance.