/sci/ - Science & Math

Hello /sci/, got a modern question here

I want to save peoples private threads, from Facebook, as pictures, for the future with the intent of having information/evidence of certain cultures and debates about the social-economic structure of our country, which happens behind closed and private groups.
Right now I edit in them, removing my avatar and putting circles around what I think is important, but would that lead to that the picture cannot be used in an eventuel future analysis, because I could potentially have edited everything to my wishes and be biased af?

I know it's a weird question, but I think it's important for other cases as well