Ever get tired of iPhoto being so s-l-o-w? This is a problem that Apple has never cracked — iPhoto is as slow now as it was back on G4 Macs back in 2004, which is remarkable considering modern computers are unimaginably powerful compared to back then.
A solution’s been built into iPhoto for some time but almost nobody knows about it. Hold down Option (Alt on some keyboards) when starting iPhoto and a dialog box will pop-up letting you switch between iPhoto libraries. You’ll only have one if you’ve never done this before, but the dialog box lets you create as many as you wish.
When you select the new library it’ll be like using a fresh installation of iPhoto — the library will be empty and waiting for you to import pictures. More importantly, it’ll be speedy.
You could have separate libraries for every vacation you go on, for example, or perhaps have just two — one for work, and one for home.
When you select a new library it becomes the default and iPhoto will always open with that library each time it starts unless you again hold down Option when starting the app and select a different library, which will then become the new default.