IPhoto Managed Library and Referenced Library. What is the difference?

Question

In a reply regarding iphoto TD mentions managed library and referenced library. What is the difference and how do you set them up?

Answer 1

A Managed Library is the default setting, photos are copied into the iPhoto Library on import. In this scenario, iPhoto is responsible for the file management.
A Referenced Library means that iPhoto does not touch the files when you import them. They remain where they were and iPhoto References them in their location.
Simply go to iPhoto Menu -> Preferences -> Advanced and uncheck 'Copy Files to the iPhoto Library on Import'.
Now iPhoto will not copy the files, but rather simply reference them on your HD. To do this it will create an alias in the Originals Folder that points to your file. It will still create a thumbnail and, if you modify the pics, a Modified version within the iPhoto Library Folder.
However, you need to be aware of a number of potential pitfalls using this system.
1. Import and deleting pics are more complex procedures
2. You cannot move or rename the files on your system or iPhoto will lose track of them on systems prior to 10.5 and iPhoto 08. Even with the later versions issues can still arise if you move the referenced files to new volumes or between volumes.
3. Most importantly, migrating to a new disk or computer can be much more complex.
Always allowing for personal preference, I've yet to see a good reason to run iPhoto in referenced mode unless you're using two photo organisers.
If disk space is an issue, you can run an entire iPhoto Library from an external disk:
1. Quit iPhoto
2. Copy the iPhoto Library as an entity from your Pictures Folder to the External Disk.
3. Hold down the option (or alt) key while launching iPhoto. From the resulting menu select 'Choose Library' and navigate to the new location. From that point on this will be the default location of your library.
4. Test the library and when you're sure all is well, trash the one on your internal HD to free up space.
If you're concerned about accessing the files, There are many, many ways to access your files in iPhoto:
*For Users of 10.5 and later*
You can use any Open / Attach / Browse dialogue. On the left there's a Media heading, your pics can be accessed there. Command-Click for selecting multiple pics.
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You can access the Library from the New Message Window in Mail:
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*For users of 10.4 and later* ...
Many internet sites such as Flickr and SmugMug have plug-ins for accessing the iPhoto Library. If the site you want to use doesn’t then some, one or any of these will also work:
To upload to a site that does not have an iPhoto Export Plug-in the recommended way is to Select the Pic in the iPhoto Window and go File -> Export and export the pic to the desktop, then upload from there. After the upload you can trash the pic on the desktop. It's only a copy and your original is safe in iPhoto.
This is also true for emailing with Web-based services. However, if you're using Gmail you can use iPhoto2GMail
If you use Apple's Mail, Entourage, AOL or Eudora you can email from within iPhoto.
If you use a Cocoa-based Browser such as Safari, you can drag the pics from the iPhoto Window to the Attach window in the browser.
*If you want to access the files with iPhoto not running*:
For users of 10.6 and later:
You can download a free Services component from MacOSXAutomation which will give you access to the iPhoto Library from your Services Menu. Using the Services Preference Pane you can even create a keyboard shortcut for it.
For Users of 10.4 and later:
Create a Media Browser using Automator (takes about 10 seconds) or use this free utility Karelia iMedia Browser
Other options include:
1. *Drag and Drop*: Drag a photo from the iPhoto Window to the desktop, there iPhoto will make a full-sized copy of the pic.
2. *File -> Export*: Select the files in the iPhoto Window and go File -> Export. The dialogue will give you various options, including altering the format, naming the files and changing the size. Again, producing a copy.
3. *Show File*: Right- (or Control-) Click on a pic and in the resulting dialogue choose 'Show File'. A Finder window will pop open with the file already selected.
*For working with an External Editor*
You can set Photoshop (or any image editor) as an external editor in iPhoto. (Preferences -> General -> 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.
Lots of folks are attracted to the idea of a Referenced Library - well I can see my files! But, frankly, unless you're an experienced Mac user I would stay well away. Not infrequently we see folks here complaining that iPhoto has "lost their photos" when what has happened is that they have imported from the Camera Card in Referenced Mode, then erased the card. Even more common, any change in the path the the file - renaming a disk, folder or file - for instance when migrating to a new machine, when trying to make space on the start up disk by moving files off the an external - also causes big problems.
If you really, really want to run a Referenced Library check out Aperture. It has tools that are much stonger in the area - like migrating tools and reconnecting tools.
Regards
TD