Now it is possible to add vertical snippets to your calendar! The process is the same as always, but now videos or photos taken in portrait mode won't have black bars on the sides.
You can easily see what your snippet will look like in both orientations by tapping on the "Rotate" button on the snippet selector screen. You can also crop the video/photo to make it fill the screen and adjust the length, brightness, and volume if you have a Pro subscription.