where to look up toyota bolt & screw dimensions or photos?

I am slowly rebuilding my Prius and have many spare bolts without part numbers. From dealer illustrations, I know which part numbers I need for what assembly, but is there a way to take a Toyota bolt or screw P/N and look up a photo or dimensions of the bolt or screw? The dealer only has exploded views of assemblies and the picture of the bolt is too small to tell. The dealer only can tell me the part numbers and brief description (such as "self-tapping screw"). I tried Google and many Toyota parts on line stores.