Something that people sharing photos of MLK walking in peaceful protests should keep in mind: By the end of his life, Martin Luther King realized the validity of violence:

One of the foundational notions of nonviolence is that in order to be respected, one must behave well and abide by the social contract: work hard, follow the rules, and prosper. The problem is that since the beginning of the Atlantic Slave Trade, black people had worked harder and followed more rules, more strictly than anyone in America. And still they found themselves in an impossible and impoverished situation. King might not have been as militant as the militants would have liked, and he may have become an even greater citizen of the world while cities were on fire, but by the time he spoke in the fall of 1967, he recognized that it would no longer be effective to tell black folks to only protest peacefully, kindly, and respectfully. They could not prosper in a game where they were the only ones expected to play by the rules. King closed that speech with a stark truth:

“Let us say boldly that if the violations of law by the white man in the slums over the years were calculated and compared with the law-breaking of a few days of riots, the hardened criminal would be the white man. These are often difficult things to say but I have come to see more and more that it is necessary to utter the truth in order to deal with the great problems that we face in our society.”

Something else they should keep in mind: One of the most commonly shared such photos was taken minutes before police moved in and brutally attacked the protesters.

MLK protest and police abuse photos