Every time I plug my iPhone into my Mac to synchronize or recharge the battery, iPhoto launches. How do I stop this from happening?

Whenever you shoot photos or videos on your iPhone, your new media shows up in the Camera Roll album of your iPhone’s Photos app. And once there’s media sitting in that Camera Roll, your Mac will think that you’ve connected a digital camera whenever you plug in your iPhone to sync with iTunes.

Since iPhoto, by default, automatically launches whenever you connect a digital camera, iPhoto will open up in anticipation that you’re going to import the photos from your digital camera (that is, your iPhone). You can turn off this behavior by going into iPhoto’s preferences, clicking on the General tab, and then choosing No Application in the dropdown labeled Connecting Camera Opens. But in the future, whenever you connect any digital camera (including your iPhone) to your Mac, you will have to manually launch iPhoto if you want to import photos.

As long as you keep your iPhone Camera Roll album empty, iPhoto won't launch when you connect your iPhone to your Mac.

A better solution might be to use iPhoto’s auto-launching behavior as a reminder to import the photos into your iPhoto library. Then, after the import is complete, tell iPhoto to delete the photos from your camera. This will remove all the photos and movies from your iPhone’s Camera Roll, thus preventing iPhoto from automatically launching again unless you have new media that needs to be imported.

If you still want to keep a copy of those photos on your iPhone, simply place them into an album in iPhoto, and then tell iTunes to synchronize that album with your iPhone.