Unable to sync photos to iPhoto from iPhoto or Photos with iTune 12.2

I was having the same issue. Not sure if it is a solid fix or just a fluke, but I ejected all devices, quit iTunes, restarted my computer, opened Photos (waited for it to complete its usual processes) then reopened iTunes 12.2 and connected devices. After all of that, "Photos" reappeared as an option in the drop down menu within the "sync photos" area. I hope this helps, I know I was freaking out a bit and researching downgrading to 12.1.

This worked for me too. When I opened Photos after the restart, it reprocessed the Photo library, and everything was fine for the sync in iTunes. For the record I updated to Mac OS X 10.10.4, iOS 8.4 and then iTunes 12.2, in that order.

Follow the following directions:

OS: 10.10.4
iOS: 8.4

Go to Photos > Preferences > (Select) Use as System Photo Library.

Go to iTunes > (Click on Photo on any idevices connected) > Photos > (Copy Photos from) Drop down list > Now you should see Photos.