string coverImagePath = "";

            if (coverImageUpload.HasFile) {
                try {
                    if ((coverImageUpload.PostedFile.ContentType == "image/jpeg" ||
                        coverImageUpload.PostedFile.ContentType == "image/png"))
                        if (coverImageUpload.PostedFile.ContentLength < 102400) {
                            coverImageUpload.SaveAs(Server.MapPath("images/bookcovers/" + Path.GetFileName(coverImageUpload.FileName)));
                            bookCoverPreview.Src = "~/images/bookcovers/" + Path.GetFileName(coverImageUpload.FileName);
                            bookCoverPreview.Visible = true;
                            coverImagePath = "~/images/bookcovers/" + Path.GetFileName(coverImageUpload.FileName);
                            uploadStatusLbl.Text = " Success";
                        }
                        else uploadStatusLbl.Text = " File size exceeded";
                    else uploadStatusLbl.Text = ".jpg and .png only";
                }
                catch (Exception ex) {
                    StreamWriter fileWriter = new StreamWriter(Server.MapPath("errorlog.txt"));
                    fileWriter.Write(ex.ToString());
                    fileWriter.Close();
                }
            }
            else if (urlTxtBox.Text.Length > 0) {
                try {
                    WebClient imgGet = new WebClient();
                    string[] fileName = urlTxtBox.Text.Split('/');
                    imgGet.DownloadFile(urlTxtBox.Text, Server.MapPath("images/bookcovers/" + fileName.Last()));
                    bookCoverPreview.Src = "~/images/bookcovers/" + (fileName.Last());
                    bookCoverPreview.Visible = true;
                    coverImagePath = "~/images/bookcovers/" + (fileName.Last());
                    urlTxtBox.Text = "";
                    uploadStatusLbl.Text = " Success";
                }
                catch (Exception urlEx) {
                    StreamWriter fileWriter = new StreamWriter(Server.MapPath("errorlog.txt"));
                    fileWriter.Write(urlEx.ToString());
                    fileWriter.Close();
                }
            }
            else uploadStatusLbl.Text = " Cover image required";