Corrupt saving eating space?

OK, I have had a problem with saving space with my iPhone 6 plus. The "other" and "documents" bars are insanely large by comparison to photos or apps. 6gigs each with photos using only 500mb. I have deleted TONS of pictures from my txt messages but it doesn't show. I can even use Messenger on my Mac and the pictures I have deleted on my phone txt still show up when I click details so they're still hidden somewhere eating away at my phone space witihout actually being on my phone. How do I fix this? My friends can't send me pictures anymore because I don't have space. I have to keep erasing and restoring my phone to clear it all out. thanks I hope you have a great day!