It’s all in the edit
Silence Live Photos
Double-click a Live Photo and click Edit to access the editing view. Here, you can use the two buttons at the bottom left of the window to, respectively, turn off the video part (the circular icon), or just mute its audio (the speaker icon).
Trim Live Photos
Below your Live Photo, you’ll see a film-strip similar to those used in video editing apps. Drag the end handles to trim a Live Photo’s video part. You can also click a frame and then Make Key Photo to change what’s shown when the pic is still.
Bounce and loop
In the menu to the right of the trim controls, the default Live option plays the video from start to finish. Switch to Loop to endlessly repeat, or Bounce to animate back and forth. The third option fakes a long exposure, creating a dreamy effect from movement in the video.
Make adjustments faster
In mac OS Sierra, clicking Adjust provided only a few options by default; you had to add more as you needed them. In mac OS High Sierra, Adjust opens a scrolling pane of collapsible sections, all of which are immediately available, and this is far quicker and easier to use.
Explore filters
In all honesty, Photos isn’t necessarily the best place to go if you’re looking for the world’s most amazing filters, but they’ve at least been shaken up a bit in mac OS High Sierra. Chrome, Process, Transfer, and Instant have all gone, replaced by professional-looking filters named Vivid and Dramatic, both with Cool and Warm variants.
Work with curves
The Curves editing tool is new to Photos and allows you to make powerful color adjustments. Click Auto and the app automatically improves your photo. You can also manually drag points on the curve, and add new ones by clicking on it. Try fashioning a subtle S shape to make the colors really pop.