Mac – Time Machine: Bulk setting Spotlight attributes failed

iPhoto puts all of your photos into a library similar to the way iTunes puts all of your music into a music in a library folder structure. That being said you could easily just copy the library from your hard drive to another. I know you want to back it up, but here is some information on how to move the library and much of the info should be useful in your soluition: http://basics4mac.com/article.php/move_iphoto_lib and http://www.hinkty.com/blogger/2006/02/how-to-move-your-iphoto-library-to.html

Also if you want to share a library between users/systems see here: http://forums.macrumors.com/showthread.php?t=158248

And lastly there is a application manager which can handle much of this in a more simplier manner called iPhoto Library Manager

Here is an answer from another forum (original poster unknown to me):

The "preparing" stage in Time Machine is usually fast, because Time Machine uses a log of file system activities to know where to find changes that need to be backed up.

But there are things you can do to make that log untrustworthy. When Time Machine discovers the log MIGHT not be valid, it does a full scan of your file system to determine what really needs to be backed up. This can take a while. On my Powerbook (and with a firewire external Time Machine drive) it can result in a "preparing" stage that lasts 20 minutes. If you let Time Machine continue, it will eventually figure out what really needs to be added to the backup disk and will continue. This, of course, is better than just gambling the log is correct or just backing up EVERYTHING again even though only a few files might actually have changed (which would take much longer and consume more Time Machine disk space).

In these early days of Leopard installs, one of the most common things you can do that will make the log untrustworthy is booting from the Leopard install DVD. Each time you do that, the next time Time Machine runs it will discover that your hard drive MIGHT have been modified without the changes being reflected in the log. So it does the full scan -- a long "preparing" stage -- to insure it gets things right.