位图随机“参数无效”错误

Question

下面的方法接收某个pdf文件的一些FileInfo，然后继续将该pdf转换为位图。这种方法似乎是随机工作的。有时它会完成而没有问题，有时它会在using (Bitmap bmp = image.ToBitmap())部分失败。一旦它到达该行，我得到“参数无效”错误。我不知道如何解决这个随机错误，也没有进一步剖析它。任何帮助将不胜感激

static void ParseOutEachBitmap(FileInfo[] pdfFiles)
        {
             string BmpPath = "C:\\temp\\bmps\\";
             if (!Directory.Exists(BmpPath))
             {
                Directory.CreateDirectory(BmpPath);
             }

            using (MagickImageCollection images = new MagickImageCollection())
            {
                MagickReadSettings settings = new MagickReadSettings();
                settings.Density = new MagickGeometry(300, 300);
                for (int p = 0; p < pdfFiles.Count(); p++)
                {
                    images.Read(@"c:\temp\pdfs\" + pdfFiles[p].Name, settings);

                    int pageNumber = 1;
                    string pdfName = pdfFiles[p].Name;

                    foreach (MagickImage image in images)
                    {
                        using (Bitmap bmp = image.ToBitmap())
                        {                          
                            Console.WriteLine("PDF Filename: " + pdfName);
                            Console.WriteLine("Page Number: " + pageNumber + " of " + images.Count);
                            pageNumber++;

                            using (tessnet2.Tesseract tessocr = new tessnet2.Tesseract())
                            {                              
                               tessocr.GetThresholdedImage(bmp, System.Drawing.Rectangle.Empty).Save("c:\\temp\\bmps\\" + Guid.NewGuid().ToString() + ".bmp");
                            }                            
                        }
                    }
                }
            }
        }