I think you need to use iPhone Data Recovery
. It can scan your iPhone 6s deeply to find the deleted photos on it. You can preview the pictures before recovering. Learn how to recover deleted photos from iPhone 6S
. Besides photos, you can also recover deleted messages, videos, contacts, call history, notes, reminders, calendars, voice memos, voicemail, safari bookmarks, Whatsapp messages and other deleted data from your iPhone 6S.