When it comes to managing files, iPhoto can be used in two modes.
1. The Managed Library and
2. The Referenced Library.
This tip will discuss these two modes and offer advice on which is best. First: definitions.
1. A Managed Library is when iPhoto manages the files. It's the default setting and when you import images to iPhoto the files are copied into the iPhoto Library package and stored there.
2. A Referenced Library is when you manage the files. You set up your own filing structure and move the images there before importing them to iPhoto. They are not copied to the Library package, just stored wherever you put them. To make a Referenced Library you go to
iPhoto Menu -> Preferences -> Advanced
and uncheck the option to copy the files into the Library on import.
At face value, and especially for new users and folks who are migrating from Windows or Linux systems the second, Referenced mode seems more attractive.
It's not. It really should be avoided, especially by those to whom it's most attractive - the inexperienced user.
Why not? iPhoto is a $15 app. It's cheap and cheerful and while it will do a lot it will not do everything. Many of its weaknesses are in the area of Referenced Libraries. So here goes with a list
1. It's more work. With a Managed Library importing is easy: connect the camera, click import. Same with deleting. Into the iPhoto Trash and empty it. With a Referenced Library you need to first get the images from the camera into your folder system, then import them. Deleting is also a two step process. Trash them from iPhoto first and then go and dig them out of your filing system.
2. You gain no advantage. None at all. When you use iPhoto it replaces the File Manager (Finder) for anything to do with your Photos. Everything you need to do is done either with or via iPhoto. So you never access the files directly. That's what a photo manager means. Even if you want to, say, edit the photos in a more powerful editor - like Photoshop. To do that you set it as an External Editor.
Preferences -> Advanced-> Edit Photo: Choose from the Drop Down Menu.)
This way, when you double click a pic to edit in iPhoto it will open automatically in Photoshop or your Image Editor, and when you save it it's sent back to iPhoto automatically. This is the only way that edits made in another application will be displayed in iPhoto.
And, of course, iPhoto makes your images available in every app on your computer though the Media Browsers: see this user tip for more:
So, again, to stress this: there is nothing you can do in Referenced Mode that you can't do in Managed mode. It's more work for the same return.
3. iPhoto lacks the tools to manage Referenced Photos. So, if you want to move all your images to another disk, for instance, you can't without making a very large amount of work for yourself, reconnecting each image one by one, or by a crash course in hacking SQL databases. If for any reason the path to the file changes then iPhoto risks losing the image and has no easy quick way to repair itself. So that means if you rename the files, rename the folders, move the images to another disk... in any of these situations you will cause problems for the iPhoto Library. So you need to think carefully and look to the future. If you run a Referenced Library, will you need more disk space in the future? If you will there's no easy way to do that with iPhoto.
This is doubly true when you have the photos on one volume or disk and the Library on another. If the path changes you will have an awful lot of work to do repairing the Library.
Some of the reasons people offer for running a Referenced Library include the following:
I have too many photos to fit on my disk.
You can run a Managed Library from any locally connected USB/Firewire/Thunderbolt disk (note: not a NAS) that is formatted Mac OS Extended (Journaled) with a wired connection.
I want to edit in another application.
See 2., above.
How can I back up my photos?
Depending on exactly what you want to back up:
a: Backing up the whole Library
Most Simple Back Up:
Drag the iPhoto Library from your Pictures Folder to another Disk. This will make a copy on that disk.
Slightly more complex: Use an app that will do incremental back ups. This is a very good way to work. The first time you run the back up the app will make a complete copy of the Library. Thereafter it will update the back up with the changes you have made. That makes subsequent back ups much faster. Many of these apps also have scheduling capabilities: So set it up and it will do the back up automatically.
Time Machine will do this, and many other apps too.
b: Just the Original photos:
File -> Export and set the Kind to Original. You can then export your original photos to your back up locations.
This User Tip
has details of the options in the Export dialogue.
What if I want to move to a more powerful app in the future?
If you migrate to Aperture then there's nothing to do as Aperture can read the iPhoto Library and vice-versa. If you want to move to a different application then exporting the images from iPhoto is the way to go. You can export to a folder tree matching your Events. See the User Tip on exporting above, for more.
I see lots of reports on here from folks who say they've lost all their photos...
When you see these queries in most - 95%+ - cases they refer to a corrupt database file and do not result in losing the actual photos. There are various tools and methods for recovering the situation and in most cases - again 95%+ - the photos are perfectly safe.
That said: the only 100% safe method for protecting your images is a comprehensive back up plan that you actually use. It's surprising how many folks report on here that they have a back up, but it hasn't been updated in months. Using a computer without a backup is like driving without a seat belt. You'll be fine if nothing goes wrong, but of something does go amiss, then it'll be a much bigger mess.
But where exactly are the files stored?
Go to your Pictures Folder and find the iPhoto Library there. Right click on that icon and choose 'Show Package Contents'. A Finder window opens at that location. Your images are within the Originals folder (called Masters on some versions)in folders named for the date and time they were imported.
Standard warning: Never make any changes within the iPhoto Library Package with the Finder or any other app. You'll trash your library if you do.
I want to share my photos with my Windows machine and it can't access the Library package
iPhoto has no cross platfom ability. Yes, a Referenced Library will allow the Windows to access the original files, but no edited images. If this is your intended usage you might want to consider using another app.
You know, I'm a grown up and I want to do these things myself. If I say I want to run a Referenced Library what would you advise?
I'd advise using Aperture. It's more expensive but part of what you get for the extra money are tools to manage Referenced files. You can move them, consolidate them, store them on other disks and so on with no problems.