Dropbox Camera Upload - too many files

I've been using the Dropbox Camera Upload feature on my Mac (with iPhoto), iPhone and iPad for some time now. I really like the idea of all my photos being stored in one location across all my devices.

However, what I've noticed is that it's created a lot of duplicated files. I recently used Drive Genius to free up some hard drive space and noticed I have over 4 GB of duplicated photos on my Mac. And most of this is due to Dropbox keeping a copy of everything.

So far all you Dropbox users, how do we keep from having all these duplicated files floating around your Mac?