I recently purchased a Mac Mini (long time PC user). The best move I've ever made. I'm a little confused as to how iPhoto operates in terms of utilizing my storage. I had 27GB of photos on my desktop (imported from an external HDD) and added them to iPhoto. Does this mean that I now have 27GB of photos on my desktop and 27GB in iPhoto for a total of 54GB taken up, or does iPhoto simply just access the photos from my desktop, so only 27GB would be taken up? If the prior is true, I have a 1.5TB external that I'd like to use with iPhoto, is this possible?