Open the Photos app
Tap Library or Albums
Select the photo or photos you want to delete
Tap the Trash icon
Tap Delete Photo or Delete [number] Photos to confirm
To delete from an album, open the album, select the photos, tap the Trash icon, and confirm
To delete permanently, open Recently Deleted in Albums
Tap Select
Tap Delete All or delete specific photos
Confirm the deletion
To recover a deleted photo, open Recently Deleted, select the photo, and tap Recover