Extracting images (png/tiff issues)

Environment:
C# .Net 2.0
Quick PDF 7.23 DLL

I am attempting to create and read image only PDF files. 
Creating the files seems to be working fine using all image formats that I have tried (PNG, JPEG, & TIFF).  I can open the files in Acrobat reader and everything looks fine, but reading them through code is giving me some trouble.

Code for writing the PDF files (formatting and non-relevant code removed):

foreach (byte[] imageContents in imageList) { int imageID = pdf.AddImageFromString(imageContents, 0); if (imageID == 0) throw new Exception("Error on AddImageFromString"); if (pdf.DrawImage(0, 0, (float)pageWidth, (float)pageHeight) == 0) throw new Exception("Error on DrawImage"); pdf.NewPage(); } pdf.SaveToFile(filePath); pdf.RemoveDocument(outputFileHandle);

Current code for extracting the images

int pdfHandle = pdf.LoadFromFile(filePath); pdf.SetFindImagesMode(1); int imageCount = pdf.FindImages(); for (int i=1;i<=imageCount;i++) { int imageID = pdf.GetImageID(i); pdf.SelectImage(imageID); byte[] img = pdf.SaveImageToString(); File.WriteAllBytes(@"C:\Testing\out" + i + fileExt, img); }

If the PDF file contains only JPEG images, I receive the images as expected.
If the PDF file contains only TIFF (CCIT Group 4) images, I receive a ton of ~35 pixel high slices of the images.
If the PDF file contains only PNG or TIFF (LZW) images, I receive the images as 24 bit bitmaps (even if the original PNG was monochrome)

I see that PNG is not defined in ImageType, which would explain why it doesn't work.

So, my question:

1. Is it possible to retrieve the original PNG images using some other method? 
   
   I saw that the renderpage function can return a PNG image, but because I may be scaling the original images when drawing them on the pages, I don't know that it would be an accurate representation of the original image.
   
   PNG is my preferred image format.  If there is no way, I may consider using JPG for color images and CCIT Group 4 TIFF for black and white images if I can figure out how to retrieve full images instead of slices for the TIFFs.

Thanks,

Hi!

how to exrtact image from the layer of pdf file using QP in C#

As to the original issue:
I've learned more about pdf and image formats, and have settled on jpeg for color.  I found methods to perform lossless rotation on jpeg images, so that format has become acceptable.  I have still not been able to get striped CCITg4 (which .net defaults to in windows 7) images to work correctly, but it looks like the quick pdf team has been doing some serious changes on CCIT handling since 7.23 so I'm hoping to get some free time to try out the latest version.  In the mean time, using black and white bitmaps with quickpdf compression has been working fine.

I have been using some DA methods to get the image's drawn size to calculate the DPI, but again it looks like some of the new features may be able to do this with an in memory file.