Rebcam doesn't access to the webcam hardware it acess to a screen
shot made by a complementary program that take shots on webcam and
update the image on web server.
I recommand you the irfan view (http://www.irfanview.com/) program
or the gimp v2.0 if you want to acquire data from webcam or scanner
hadware (in fact all windows twain capable hardware can be read by
REBOL is actually unable to interact directly with the Windows twain
module (beacause of compatibility issue)