I am brand new to Macs as of this past week. I have imported all of my photos to iPhoto. I have made some changes and want to get everything backed up to my external drive. How can I accomplish this? When going to iPhoto, I noticed the Share > Burn option, but this appears to be only for CDs/DVDs. I also tried simply highlighting all of my "Events" folders and dragging them to external drive, but it would not allow me to do this. Any best practices out there for this?