Mac Mini with NAS and Windows HDD

Hi

I've gone from an old windows laptop to a Mac Mini. I have some pictures/videos stored on it's 500gb memory but i want to store everything in one central place so i've ordered this http://www.dabs.com/products/western-digital-2tb-my-book-live-personal-cloud-sto rage-nas-77V8.html

I have a 2TB external storage device formatted for windows and i'm too afraid to try and partition in case it all goes wrong.

if i have the Mac Mini, iPad and iPhone all storing photos on the NAS can i partition the NAS and put my existing photos on to keep the windows photos visable from all devices?

I dont actually know how i store images onto a NAS, do i simply put in a memory card and drag files to the NAS drive in finder? Or can I use iPhoto as normal and somehow point it to the NAS so it saves images there and allows me to view them still in iPhoto from the Mac Mini?

my other idea is to partition the NAS and put all the windows photos on it, then reformat the 2TB external storage and use this as the Mac Minis storage so i can still use iphoto as normal but the NAS will be backing everything up as I go.