For creating the PDF preview, first have a look at some other discussions on the subject on StackOverflow:
- How can I take preview of documents?
- Get a preview jpeg of a pdf on windows?
If these don't answer your question, you can try a couple more things:
- You can get a commercial renderer (PDFViewForNet, PDFRasterizer.NET, ABCPDF, ActivePDF, ...).
Most are fairly expensive though, especially if all you care about is making thumbnails.
- There is a CodeProject article that shows how to use the Adobe ActiveX, but it may be out of date, easily broken by new releases and its legality is murky.
- Install GhostScript on the server and request rendered thumbnails of any page from it.
I did a small project that you will find on the Developer Express forums as an attachment.
Be careful of the license requirements for GhostScript through.
I use it for an internal software and it's working pretty well.
Hope this helps.