Photos can be deleted individually in the Oppo smartphone's Gallery app or multiple photos can be deleted at once using the edit mode, and deleted photos are moved to the Trash, where they are automatically deleted after 30 days.

Android 10 | ColorOS 7.0
Step 1:  Open the  Photos -App
Step 2:  Tap on  Photo  you want
Step 3:  Tap on  Delete
Step 4:  Confirm with  Delete Photo
  1. Open the Photos-App
  2. Tap on Photo you want
  3. Tap on Delete
  4. Confirm with Delete Photo

Oppo Instructions