//public string guid { get; set; }
        //Convert the pdf into Single Image.
        public static void ConvertSingleImage(string filename, string outputDir)
        {
            PdfToImage.PDFConvert pdfConverter = new PdfToImage.PDFConvert();

            try
            {
                pdfConverter.RenderingThreads     = 5;
                pdfConverter.TextAlphaBit         = 4;
                pdfConverter.OutputToMultipleFile = false;
                pdfConverter.FirstPageToConvert   = -1;
                pdfConverter.LastPageToConvert    = -1;
                pdfConverter.FitPage      = false;
                pdfConverter.JPEGQuality  = 10;
                pdfConverter.OutputFormat = "jpeg";

                System.IO.FileInfo input  = new FileInfo(filename);
                string[]           str    = input.Name.Split('.');
                string             output = outputDir;
                while (System.IO.File.Exists(output))
                {
                    File.Delete(output);
                    output = outputDir;
                }

                pdfConverter.Convert(input.FullName, output);
            }

            catch (Exception ex)
            {
            }
            return;
        }