using (var imgTool = new IEImage())
{
	var ext = Path.GetExtension(filename).ToLower();

	img.IOParams.FileFormat = IEFileFormats.PDF;
	
	var resolution = Math.Max(TwainParams.XResolution.CurrentValue, TwainParams.YResolution.CurrentValue)
	img.IOParams.JPEG_ColorSpace = IOParams.JPEGColorSpace.RGB;
	
	if (resolution <= 150)
	{
		img.IOParams.JPEG_Quality = 50;
	}
	else if (resolution <= 300)
	{
		img.IOParams.JPEG_Quality = 65;
	}
	else
	{
		img.IOParams.JPEG_Quality = 80;

	}
	
	img.IOParams.PDF_Compression = IOParams.PDFCompression.JPEG;
	imgTool.CreatePDFFile(filename);

	for (var i = 0; i < _imgThumbnails.ImageList.ImageCount; i++)
	{
		_imgThumbnails.ImageList.CopyTo(i, imgTool);
		imgTool.SaveToPDF();
	}
	imgTool.ClosePDFFile();
	
}