macOS doesn’t handle large iPhoto libraries well and it’s frustrating. The Photos app is very slow. My library only fits on an external disk, which Photos has to be tricked into supporting, and it’s always running mysterious processing tasks in the background, eating my CPU and disallowing my disk to eject. I considered moving back to Flickr, but it’s fallen way behind Google Photos’ site and iOS app. I’m hesitant but considering paying to move my entire library to Google.