View photos on Apple Watch
Photos from the iPhone album of your choice appear in the Photos app 
on your Apple Watch. When you first get an Apple Watch, it’s set to use your Favorites album—photos you tagged as favorites—but you can change the album it uses. And, you can show a photo on your watch face.
Browse photos on Apple Watch
Open the Photos app on your Apple Watch and use these actions to browse your photos.
Tap a photo to view it.
Swipe left or right to see other photos.
Turn the Digital Crown to zoom, or drag to pan a photo.
Zoom all the way out to see the entire photo album.
View a Live Photo on Apple Watch
Look for the Live Photo symbol 
in the bottom-right corner of a photo, then touch and hold the photo.
For more information about Live Photos, see iPhone User Guide.
Show a photo on the watch face
While browsing in the Photos app on your Apple Watch, firmly press any photo, then tap Create Watch Face. Or, add a new Photos watch face. See Apple Watch faces and their features.
Tip: You can easily create a watch face on your iPhone with iOS 11 or later. Open the Photos app on your iPhone, tap a photo, tap 
, then tap Create Watch Face.
View a photo memory on Apple Watch
In watchOS 5, you can view photo memories—favorite and forgotten moments from your photo library—on your Apple Watch.
See a recent memory from the Siri watch face: Choose the Siri watch face, then tap a memory.
Create a Memories watch face: Open the Apple Watch app on your iPhone, tap Face Gallery, tap Memories under the Photos heading, then tap Add.
Take a screenshot of Apple Watch
In the Apple Watch app on your iPhone, tap My Watch, tap General, then turn on Enable Screenshots.
Press the Digital Crown and the side button at the same time to take a picture of the screen.
Screenshots are saved in Photos on your iPhone.