Ask someone older than 50 where they were when they heard President John F. Kennedy was killed, and they can probably tell you where they were.
But are the images fair game for commercial purposes or off limits?
A recent ad that has popped up in snowboarding magazine is raising some eyebrows. The ad shows an altered image of Bob Jackson's Pulitzer Prize-winning picture of Jack Ruby murdering Lee Harvey Oswald in the basement of the Dallas Police Department.
In the altered image, Dallas police detective Jim Leavelle, who was handcuffed to Oswald, is wearing a yellow ski jacket and a T-shirt while Ruby sports a red-and-blue one.
The text of the ad says, "Killing it."
Leavelle said he can see how some people would be offended by the liberties taken with the infamous historic event, but said he is more annoyed with conspiracy theorists who've attempted to put words in his mouth.
"I have put up with so much in the last 46 years, something else don't really faze me," he said. "I've been put in worse positions from time to time."
An ad for a local Dallas bicycle run features a picture similar to the one take by Dallas Morning News photographer Walt Sisco. The picture shows Kennedy in the motorcade, but the image features a splatter of blood behind Kennedy's head.
The image was originally an album cover for punk band The Misfits in the 1970s.
The ad prompted dozens of comments to the bicycle company's Web site. The store was closed Monday.
Bad impressions from a questionable ad can bring a severe negative reaction, said Dan Howard, a marketing professor at Southern Methodist University.
"In my judgment, it is poor judgment, in that it is bad marketing," he said. "From what I saw in terms of these ads, I think they are an inappropriate use, and they are ugly, and there are likely to be a whole lot of people that are not very happy with that."
A spokeswoman for the Sixth Floor Museum said it doesn't have any comments about the ads specifically, but Deborah Marine of the museum said:
"The Sixth Floor Museum at Dealey Plaza has a comprehensive rights and reproductions program related to its collections. The program has three major objectives: to administer copyright concerns, to manage internal and external use of images in our collection and to protect the integrity of the collections. Information about the collections and rights and reproductions program can be found on the museum Web site, www.jfk.org.