iOS 9.3 have a new feature "Apple Notes password protected" You can use that feature to hide your photo with a password. Follow the steps 1. New note. 2. Choose your photo that you want to hide. 3. Lock your note with a "new feature" and set your password. 4. Delete your photo in camera roll. 5. Do not forget to remove from "recently deleted" 6. When you want to see or use your photo go to note, put your password and save it to your camera roll again. **Your photo from note have the save resolution as the one that you deleted so don't worry about quality.