Enabling the "Edit in external editor" menu option in iPhoto

While iPhoto is neat for basic photo editing, I primarily use Photoshop for serious adjustments (love that Shadow/Highlight tool). I was surprised to find that when I Ctrl-clicked my photos, the "Edit in external editor" option was grayed out. Here's how to set it up.

In iPhoto Preferences, under General, set "Edit photo:" to "External editor" (this controls what happens when you double-click thumbnails). Pick Photoshop (or whichever application you plan to use). Close Preferences.

Now, I normally set this option to "Using full screen" because it's a very smooth, distraction-free environment for basic tweaking. We set the above option just so it would show up in the context menu when Ctrl-clicking a photo. Try it now - "Edit in external editor" will be available.

You can now go back to Preferences and change the "Edit photo" option to anything else - the external editor has been set and the option will always be available.