Best Answer Photographa , 16 November 2013 - 09:45 AM
iPhoto creates a file in the Pictures folder on your Mac. It's called "iPhoto Library" and the single file is a collection of all your original photos metadata and edited versions of photos.
If you need to free up disk space, you can drag this file to an external drive. If you hold down the Option key while opening iPhoto, you will be asked which iPhoto Library to use, and you can select the one on the external drive or have iPhoto create a new empty library for you on the Mac.
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