Reclaiming disk space is the goal of the next iPhoto tool: iPhoto Diet. iPhoto might be the biggest disk space hog of any Apple application. In fact, most users find that their iPhoto library folder accounts for as much (if not more) disk space than their iTunes library.
One major reason why iPhoto tends to use so much disk space is that it maintains a backup copy of every photo that you edit. So if you rotate a photo and save it, you now have two copies of that photo (one rotated and one in its original position). Needless to say, if you make multiple series of changes to photos or even just do minimal editing (rotating, cropping, red-eye reduction, and so on) to even a small portion of your photos, you’ll lose a noticeable amount of disk space to these backup copies—and in many cases, you’ll never want to revert to these originals. (Who needs a picture of Seattle’s Space Needle on its side because you had to tilt your camera to fit it all in?). Even more space-hogging happens if you have iPhoto set up to work with an external photo editor (such as Photoshop); it automatically creates a backup of all photos that you import, regardless of whether you’ve edited the photo or not.
iPhoto Diet enables you to easily process your iPhoto library and remove these backup files to reclaim disk space. You can choose to remove all backups, remove backups of rotated photos, or remove backups where the original photo and the backup are identical. iPhoto Diet can also try to recover disk space by removing thumbnail images displayed in the Finder from your photos as well as stray folders that iPhoto is no longer using. Simply put, iPhoto Diet is a great tool if you have limited storage space (such as the internal hard drive of a portable Mac).
iPhoto Diet also offers some organizational capabilities. It has a duplicate locator feature, although it is not nearly as advanced as Duplicate Annihilator’s. It can also search your iPhoto library for photos that have been imported but not added to any album. This is a nice feature if you regularly import photos but don’t organize them immediately because you can often end up have a few stray photos that you would normally have to scroll through your library’s contents to locate.