The TWAIN drivers that are included with a scanner are the only ones that will work (we just found this out here after spending weeks trying to use the wrong drivers for a Mustek scanner). Although they appear to be a software program for scanning, they're actually the drivers for the scanner along with an interface for doing it. You can't just swap them out for something else. All your image editing applications do is call up those drivers and the interface in order to have the image scanned, then passed back to the application. TWAIN drivers all use a standard call so that all applications will be able to call them up, so they're not dependent on the application being used.