What this means is that when I want to set one of my pictures as a desktop background, I hate using the System Preferences window to do it. It’s very small, and navigating through five thousand images to find the one I want within that pane is frustrating.
This, Apple, is not user-friendly.
Fortunately, you can set this preference directly from iPhoto, which makes viewing your images to choose the correct one much nicer.
Here’s how. In iPhoto, find the picture you’d like to use. (If you choose an event instead of a single photo, it’ll automatically set your desktop image to change every thirty minutes.) Click to select it, and then choose the menu item Share > Set Desktop.
That’s all there is to it. It’s so easy, even an iPhoto slacker like me can handle it.