Well the tweet is under whatever terms Twitter imposes on you for using their service. But in this particular case, someone tweets a photo some other originatio

Well the tweet is under whatever terms Twitter imposes on you for using their service. But in this particular case, someone tweets a photo some other origination copyrighted. I mean, technically taking a photo of a movie poster and tweeting it is infringement, but most movie companies have better things to do than go after you for it, especially if it's not disparaging and may promote the movie.