How to transfer original image files to an external or network drive on PC?

Hello, I am trying to create an extra, shared backup of all of my original image files. It would be on shared PC drive that I can access over a wifi network. The files would also be accessed by a PC user. I would like the original master image files, not the "photos" library file, if that makes sense. I have been trying to figure out how to do this, with no luck. I have nearly half a terabyte of photos to transfer. Can I not just "export" my photos library to an external drive? Any suggestions or help would be very much appreciated! Thank you.