Sure, sorry - I should have put that in my original post. It's Session 243, iPhoto UI Progression and Design, with Randy Ubillos himself.

Probably https://developer.apple.com/videos/wwdc/2012/?id=243 I haven't watched it yet, but it's been on my to-watch list for a while now.

The session name is 'iPhoto for iOS: UI Progression and Animation Design'. It's under Essentials.