VintaSoft Imaging .NET SDK and Plug-ins Discussions

I have some code that opens a multi-page TIFF (tFile = new TiffFile(e.FullPath)) and then iterates through the pages to split, based on blank page detection, into individual PDFs .

This code below (tested with the trial component):
a) won't save at col.Save(aPath, pdf). aPath is correct. No PDF is produced. Is it because it is a trial?
b) craps out the SetImage at the start of the loop (img.SetImage(pg.GetImage())) after the first save-and-clear is called, with a System.NullReferenceException. If I comment out the Clear() just after the red line, I don't get the exception. I suspect that when I col.Add(img) to col, and then later call col.Clear(), I end up disposing the img object? If so, how should I get the TIFF pages into col "by copy"?

            TiffPageCollection pgs = tFile.Pages;
            if (pgs.Count == 0)
            {
                logWriter.WriteLine("-> No pages in multi-tiff. Done.");
                logWriter.Close();
                if (tFile != null)
                    tFile.Dispose();
                return;
            }

            VintasoftImage img = new VintasoftImage(pgs[0].GetImage()); 
            ImageCollection col = new ImageCollection(); // will hold collection of processed TIFFs
            PdfEncoder pdf = new PdfEncoder(true, 80);
            int pgIdx = 0;
            int pdfIdx = 1;
            float blankThreshold = float.Parse(ConfigurationSettings.AppSettings["blankThreshold"]);
            string aPath = "";
                
            // begin processing
            foreach (TiffPage pg in pgs)
            {
                try 
                { 
                    img.SetImage(pg.GetImage());
                }
                catch (Exception err)
                {
                    logWriter.WriteLine(err);
                    logWriter.Close();
                    if (tFile != null)
                        tFile.Dispose();
                    return;
                }

                if (img.IsBlank(blankThreshold))
                {   // cut it up
                    logWriter.WriteLine("-> Blank page at position: " + pgIdx);
                    if (col.Count > 0)
                    {   // save it if there meat in the collection 
                        aPath = e.FullPath.Replace(".", "_") + "_" + pdfIdx + ".pdf";
                        logWriter.WriteLine("-> Creating PDF with " + col.Count + " pages.");
                        col.Save(aPath, pdf);
                        col.Clear(); 
                        logWriter.WriteLine("-> PDF saved at: " + aPath);
                    }
                    pdfIdx++;
                }
                else
                {   // process, clean and add
                    img.Deskew(BorderColor.AutoDetect, 5, 5);
                    //img.Despeckle(8, 25, 30, 400);
                    col.Add(img);
                }

                pgIdx++;
            }