Importing overview
You can import photos from a camera, from a mobile device, from email, from a storage device, or from a hard disk.
By default, iPhoto copies (duplicates) photos into the iPhoto library, leaving the originals in their current locations. You can modify this behavior in the Advanced pane of iPhoto preferences.
When you import photos, they’re automatically organized into Events. You can manage Events and define the timeframe and grouping of Events in the General pane of iPhoto preferences.