After 1.5 years, Android's Photo Picker is finally preparing to get Google Photos integration! This will let the Photo Picker select photos and videos stored in the cloud.

You can learn more details and see screenshots of this feature from this article on Android Authority.

Android Authority

Google Photos cloud content will soon appear in Android's Photo Picker, finally

Android's Photo Picker is currently limited to your local media files, but that could change soon as Google Photos looks to add support.