How many times has a demonstrable lie spread around before it's been discredited? And why is it so hard to believe that TR might have either lied deliberately or got his facts wrong? It would hardly be the first time that someone has spread nonsense on the internet, maliciously or through carelessness, and it will not be the last either.
Put another way, I am not even sure what the point you are making is -- if, as in the case in question, the photo *was* mistaken, and TR shared it anyway, then either he knew it was misattributed (in which case it's a deliberate attempt to spread disinformation in the -- frankly, quite reasonable -- hope that his supporters won't bother to check and don't care anyway); or he did not, in which case *he's* the one who needs to check his sources more carefully. It doesn't matter, then, whether this was neglect or malice.