When you use iCloud’s Photo Stream feature, you shouldn’t have to plug your iPhone or iPad into your Mac to sync images very often. If you’re like me, though, you connect your device to your computer occasionally to charge or what have you, and you get frustrated at iPhoto insisting that it needs to launch when you do so. Yes, iPhoto. I understand that you want to import images for me, but iCloud’s already done that. Thanks anyway.
There is a way keep the program from opening when you plug in a device, however. To do that, launch iPhoto, then choose iPhoto> Preferences. Click on the “General” tab, and toggle “Connecting camera opens” to “No application.”
After that, iPhoto won’t open by itself when you plug in an iOS device (or a camera!), so if you’ve got images you actually do need to import, you’ll have to open the program manually.
Keep in mind that it’s a good idea to sync to iPhoto occasionally (even if you’ve got Photo Stream turned on) just to make sure that no images have been missed. Also, since Photo Stream doesn’t work with video, be sure to plug in every once in a while to import those into iPhoto for safekeeping. You wouldn’t want to lose those thirty seconds of slo-mo video you took of your spouse singing, would you? I know I wouldn’t.