One of iPhoto’s main jobs is to keep all your photos together in one place—one icon that’s easy to copy to a backup disk of any kind.

That all-important icon is the iPhoto library, which resides inside the Pictures folder of the Home folder that bears your name. If your user name (the short name you use to log into OS X) is Casey, for example, then the full path to your iPhoto library file from your main hard drive window drive is Macintosh HD→Users→Casey→Pictures→iPhoto Library. Alternatively, pop open a Finder window and choose Go→Home, and then double-click the Pictures folder.

As described in Chapter 2, the iPhoto library contains not just your photos, but also a huge assortment of essential elements:

To prepare for a disaster, you should back up all these components.

To perform a complete backup, quit iPhoto and then Option-drag the iPhoto library icon to another location on your hard drive. However, copying it to another spot on the same disk means you’ll lose both the original iPhoto library and its backup if, say, your hard drive crashes or an asteroid hits your computer. Copying it to a different hard drive—to another external hard drive or another Mac via the network—is the best route—drag the icon to an external drive to begin the copying (no modifier key required).

You’d be surprised at how cheap hard drives are these days. As of this writing, you can buy a 1-terabyte hard drive (that’s 1,000 gigabytes) for way under $100, for goodness’ sake—and hard drive prices-per-gigabyte only go down.

Burning a CD or DVD is handy for backing up your photos, transferring them to another computer (even a Windows PC), mailing them to somebody, or offloading (archiving) older files to free up hard drive space. You can buy blank CDs and DVDs incredibly cheaply in bulk via the Web.

CDs can store about 700 megabytes of data. Single-layer DVDs store roughly six times as much data as a CD, for a total of 4.3 gigabytes. Dual-layer DVDs—like the ones you get when you rent or buy a Hollywood movie—are more expensive but hold twice the data of their single-layer brethren (8.5 gigabytes). So, if your iPhoto library file is smaller than, say, 4 gigabytes, you could burn it onto a single-layer DVD; if it’s smaller than 8 gigabytes, you can squeeze it onto a dual-layer DVD. With this method, your entire iPhoto realm remains intact.

However, if your iPhoto Library file is larger than 8 gigabytes, you’ll need to export your photos and videos first, and then burn the individual files to disc instead. The downside to this approach is that, depending on the export options you pick, any edits you’ve made to the photos become permanent and you lose the organizational structure you’ve worked so hard to create in iPhoto (like folders and albums). If you’ve added flags or star ratings, they get stripped out too, though keywords and location tags can remain intact if you turn on those two options in the Export dialog box as described in step 1 below).

Whether you’re burning your entire iPhoto library onto disc, or individually exported photos, video, or a slideshow, the process is the same. Here’s how it works:

There’s another approach: In the Finder, choose File→New Burn Folder. A new folder cleverly named—you guessed it—Burn Folder appears on your desktop. Name it anything you want, and then drag your files inside. Now open the folder and click the Burn button in the upper-right corner. The Mac asks for a blank CD or DVD and then walks you through the process of burning it. (This method is especially handy when you don’t have any blank discs lying around. Simply gather up the files you want to back up, and then perform the burn whenever you get around to buying some discs.)

Either way, once you’ve tested that the disc(s) you’ve burned work, you can delete the exported files on your hard drive to reclaim some space.

The one disadvantage of the abovementioned offload-to-disc technique is that it takes a big hunk of your photo collection offline, so that you can no longer get to it easily. If you suddenly need a set of photos that you’ve archived, for example, you have to hunt down the right disc. That could be a problem if you happen to be in New York and need the photos you left on a DVD in San Francisco.

Here’s a brilliant solution to that disc-management problem: Turn your discs into disk image files on your hard drive. These files are basically virtual CDs that you can keep on your hard drive at all times.

To create one, open Disk Utility (which sits in your Applications→Utilities folder); then insert the CD or DVD you’ve burned (Burning Files to CD or DVD). In the left pane of the Disk Utility window, click the disc’s icon (see Figure 12-2).

Figure 12-2. Be sure to click the CD or DVD icon bearing a plain-English name, like “iPhoto Library” or “Wedding photos” as shown here (it’s usually the last one listed). Don’t click the icon bearing your CD burner’s name, like “MATSHITA DVD-R.”

Then choose File→New→“Disk Image from [disc name],” or click New Image at the top of the window (circled in Figure 12-2). In the resulting Save As dialog box, you can type a name for the disk image you’re about to create. You can even password-protect it by choosing “128-bit AES” from the Encryption pop-up menu. Next, choose a location for the disk image, such as your desktop, and then click Save.

You’ve just created a disk image file whose name ends with .dmg. When you want to view its contents in iPhoto, double-click the .dmg file’s icon. You’ll see its contents appear in the form of a CD icon in iPhoto’s Source list, just as though you’d inserted the original disc.

You can spin off numerous chunks of your iPhoto collection this way, and “mount” as many of them simultaneously as you like—a spectacular way to manage tens of thousands of photos, chunk by chunk, without having to deal with a clumsy collection of discs.

Now that iPhoto can hold tons of photos in a single library, there’s not as much need to split it into separate libraries as there once was. Still, there are two good reasons why you might want to consider it:

Creating New Libraries

iPhoto includes a tool for creating fresh libraries and switching among several of them. Here’s how to use it:

1. Quit iPhoto.

   You’re going to do the next step in the Finder.

2. While pressing the Option key, open iPhoto again.

   When iPhoto starts up, it senses that you’re up to something and offers you the chance to create a new library or choose an existing one (Figure 12-3).

3. Click Create New, fill in the Save As dialog box that opens, and then click Save.

   You’re offered not only the chance to create a new library, but also to choose a location for it if it’s not your regularly scheduled Pictures folder. Type a name for the new library (Wedding Photo Library or whatever), and then click Save. When iPhoto finishes opening, all remnants of your old iPhoto library are gone. You’re left with a blank window, ready to import photos.

Figure 12-3. If you open iPhoto while holding down the Option key, the program invites you to pick which library you want to open or to create a new one. If your goal is to start a fresh library for the new year, click Create New and give it a name. To pick an existing library, either double-click it in the list or click it once to select it and then click Choose.

Using this technique, you can spawn as many new photo libraries as you need. You can archive the old libraries on CD or DVD, move them to another Mac, or just keep them somewhere on your hard drive so that you can swap any one of them back in whenever you need it.

As for how you swap them back in, you have two options: Apple’s way and an easier way.

Swapping Libraries (Automatic Method)

If you think that Option-key business sounds a little disorienting, you’re not alone. Brian Webster, a self-proclaimed computer nerd, thought the same thing—but he decided to do something about it. He wrote iPhoto Library Manager, a $30 program that streamlines the process of creating and swapping iPhoto libraries (see Figure 12-4). If you’ve got the extra cash, waste no time in downloading it from Brian’s site, www.fatcatsoftware.com/iplm. (The free version lets you swap libraries, but not much else.)

The beauty of this program is that it offers a tidy list of all your libraries, and you can switch among them with two quick clicks.

Figure 12-4. iPhoto Library Manager lets you quickly switch among as many iPhoto libraries as you want. Select a library from the list on the left and the other columns show its albums and thumbnails. (The active [open] library has a checkmark next to its name.) You can download the program for free, though the $30 version includes more features.

Here are a few pointers for using iPhoto Library Manager:

• The program doesn’t just activate existing iPhoto libraries; it can also create new libraries for you. Just click Create Library in the toolbar, choose a location and name for the library, and then click OK.

• You still have to quit and relaunch iPhoto for a change in libraries to take effect. Conveniently, iPhoto Library Manager includes Quit iPhoto and Launch iPhoto buttons in its toolbar (just widen the program’s window if you don’t see them).

• iPhoto Library Manager is fully AppleScript-able. If you’re handy with writing AppleScript (discussed in Chapter 11), then you can write one that swaps your various libraries automatically with a mere double-click.

You certainly can combine the photos of two Macs’ photo libraries—just export them from one (File→Export) and then import them into the other (File→“Import to Library”). As a result, however, you lose all of your album organization, your ability to undo edits, your ratings and comments, and so on.

Your next instinct might be: “Hey, I know! I’ll just drag the iPhoto library icon from computer number 1 into the iPhoto window of computer number 2!”

Big mistake. You’ll wind up with duplicates or triplicates of every photo in the viewing area, in one enormous, unmanageable, uncategorized, sloshing library. You could also use CDs or DVDs as intermediaries, but that’s time-consuming and uses up blank discs.

The only sane way to merge libraries is to use iPhoto Library Manager, described on Swapping Libraries (Apple’s Method). For $30, you can unlock some features that aren’t available in the free version—including a miraculously simple Merge Libraries command. All you do is click Merge Libraries in the toolbar at the top of its window, and then proceed as shown in Figure 12-5.