Images/videos are considered speech. There was actually a few different First Amendment cases concerning different images/videos being made illegal, but of those only one ban clearly stuck (a second ban was struck down but reinstated with slightly different laws and is still waiting a second SCOTUS ruling on it).

(As a side note to any lawyers, is text protected speech when it originates as a description of an actual harmful act of which video/images would not be legal speech? I don't think it was made illegal, but I wonder if it could be (at least if it were at some level of detail).)