How to use Google Photos watch face on Pixel Watch

In addition to the plethora of other watch faces available, there's a special Google Photos watch face on the Pixel Watch. It lets you add up to 30 different photos, which will be cycled through every time you glance at your wrist.

source https://www.androidcentral.com/wearables/how-to-use-photos-watch-face-on-pixel-watch