How to Move Your iPhoto Library to an External Hard Drive
Apple's iPhoto software is included as part of the iLife suite of software programs designed for digital media entertainment and management. The iPhoto software is similar to other photo management programs in that it offers the ability to organize, tag and sort your photos. Additionally, iPhoto offers basic editing functions such as cropping and removing red-eye. With an external hard drive connected to the computer, the iPhoto library can be moved for portability between multiple computers.
Connect the external hard drive to the computer.
Open a new Finder window by clicking on the blue Finder icon on the Dock.
Click your username to go to your home folder.
Double-click the "Pictures" folder.
Click and drag the "iPhoto Library" icon to the external hard drive. This process copies the iPhoto library.
Delete the "iPhoto Library" icon from the "Pictures" folder. This completes the act of moving the library instead of just copying it.