Do you want to disable the automatic action of transferring the photos when you connect the iPhone device?
If you want to disable the automatic action for a particular device such as the iPhone device, you can do so by choosing the appropriate action for that device under Autoplay options.
Refer to the link to do so:
“AutoPlay: Frequently asked questions”
“How do I make sure that I'm always asked to choose an action for a device or type of media?”