Open the Photos app
Tap Library or Albums
Tap Select
Choose the photos you want to remove
Tap the Trash icon
Tap Delete Photos to confirm
To delete from an album, open the album, tap Select, choose photos, then tap the Trash icon
To delete all photos from an album, open the album, tap Select, tap Select All if available, then tap the Trash icon
To remove photos from the iPhone and iCloud, make sure iCloud Photos is enabled before deleting
To permanently delete photos, open Albums, tap Recently Deleted, tap Select, then tap Delete All or delete specific photos
To recover deleted photos, open Recently Deleted, tap Select, choose the photos, then tap Recover