iPhoto’s image-editing tools make it simple to adjust color balance, rotate a photo, remove red-eye, and make all sorts of other changes. But what if you need to add a box around a subject or want to use a Photoshop filter? You could, of course, drag the image in question out of iPhoto, open it with the other program, and then reimport the changed file to your iPhoto library. But that’s tedious, and I don’t like tedium. Let’s all use iPhoto to avoid extra work! Adding to all the other things I do to avoid extra work, I guess.
So to first set which application you’d like to use to edit your photos, choose the menu item iPhoto > Preferences. From there, click on the Advanced tab, and toggle the Edit Photos drop-down menu to In application.
iPhoto will then bring up the familiar “Open” dialog box for you to navigate to your preferred program.
OK, so you’ve picked what application you’d like to edit your images with. What does that mean? From now on, whenever you select a photo and either click the Edit button at the bottom of iPhoto’s window or choose Photos > Edit Photo, iPhoto will duplicate your image and open that duplicate into the program you selected above. Why does it duplicate the image first, you ask? Because after you make edits using iPhoto’s internal tools, you can always choose Photos > Revert to Original to undo everything, but iPhoto can’t revert changes made by Photoshop, Preview, or any other external editor. So you’ve still got a safety net if you really screw things up.
So edit your photo in the alternate program and save it. When you do so, iPhoto will update the duplicated image in your library with your changes.
Also, now that you’ve told iPhoto which other editing program you prefer, you can choose whether to edit within or outside of iPhoto on a case-by-case basis. To do this, right- or Control-click on an image. From the contextual menu, select Edit in iPhoto or Edit in External Editor. Handy!