For the last 5 years I've have collected a lot of pictures. Mainly travel and family pictures. The problem is that I was not particularly strict when it came to my workflow.
Right now I have 3 USB hard drives + 2 computers on which I keep pictures. Some are on more than one device, others are not. To solve this, I just bought a nice big NAS where I want to consolidate my entire library.
What is the simplest way to do this? I would prefer to rely on free programs (I'm running OSX).