Updated: Aug 10, 2020
When you delete something in your device. Make sure you use good App. to delete your data. And before you factory reset your phone you should wipe your empty space. You need to understand not because you delete photo, document, or other data that means it's really deleted. Even if you factory reset your device, wipe, your device data can be recovered. Use data eraser:
When you did your factory reset, load your device with (JUNK photos and data) and restart all process again. Make some test and try to recover your data after you wipe out. And use different App to recover your data. If it’s impossible to recover data, it’s mean that you successfully really wipe your phone.