Explained... The Photos interface
1 The new sidebar
The sidebar in macOS Sierra was optional (View > Show Sidebar), but now it’s persistent. If you always want it in fullscreen, too, turn on View > Always Show Toolbar and Sidebar in fullscreen.
2 Your library
Key custom albums that were previously scattered around the sidebar are now housed under Library. Here, you find the likes of Memories and Favourites, along with the Recently Deleted album.
3 Revamped imports
Click on Imports for a chronological feed of photos and images you’ve added to Photos. Note these are grouped by import and not date, and so the likes of Photo Stream entries show up individually.
4 New media types
Under Albums in the sidebar you’ll find a Media Types folder, which provides fast access to specific types of images, such as screenshots, selfies, and the new long exposure option (from Live Photos edits).
5 Quicker editing
In macOS Sierra, you could rotate or favourite a selection of snaps using menu options, but now there are bespoke buttons in the toolbar for doing so. The selection number’s much clearer, too.
6 Filter options
Enter a library category, and you’ll see a Showing filter menu. This defaults to All Photos. Click it to limit the view to only specific image types, or images that match user-defined keywords.