If you are using iOS 9 version on your iPhone or iPad then deleted photos does not get deleted permanently from your device. It gets stored in the folder name as “Recently Deleted” in the photos app in iOS 9. 

As mentioned above when you delete images in iOS 9 it gets stored in “Recently Deleted” folder, it means that pictures does not get deleted permanently and it can recovered from there very easily. Your photos remain there for 30 days and anyone can restore it on your iPhone or iPad.