I have been a very long and vigorous user of PDFCreator and have seen it add support for formats like JPG, PNG and so on which make it the most versatile program in its class there is a new and upcoming format which if added to pdfcreator would improve its flexibility and usefulness for endusers. The format is DjVu : see this link for more details or on Wikipedia.
Also here you will find the technical specs for a DjVu document (see the White Papers & Tech Docs section).
If you could add support for creation of DjVu support it would be very nice and add to the flexibility of PDFCreator.