The number of photos stored on your AppleWatch depends on available space. To save space for songs or other content, you can limit the number of photos stored on it.
Open the AppleWatch app on your iPhone.
Tap My Watch, then go to Photos > Photos Limit.
To see how many photos are on your AppleWatch, do one of the following:
Open the Settings app
on your AppleWatch, then go to General > About.
Open the AppleWatch app on your iPhone, tap My Watch, then go to General > About.
To see how much space is used for your photos, open the Settings app on your AppleWatch, then go to General > Storage. To do this on your iPhone, open the AppleWatch app, tap My Watch, then go to General> Storage.