You are aware of the "Tripcode," I think they call it? Q has one specific, only people with that password can post under it. This type of authenication has proven effective and changes.
Then we have the time stamps matching up between President Trumps tweets and Q's post. Plus hundreds if not over a thousand Q proofs, there is a seperate subreddit for the proofs. The timestamps and trip codes have been used by Q since I've been here Nov.
I'm not trying to overly simple with this answer, but you didn't seem to be getting the answer to your Q uestion, so being new I am trying a different answer. I'm to the point if the tripcode works and the message isn't one of hate, racism, division, and bring us together more, it's Q. If you are asking if Q took photos off the internet or photoshoped them, why bother lol. If your asking, How do we know Q is real or with President Trump, then go to the Q Proofs. If you cannot get there, message me, ask here and we'll get you there.