The exhibition at the Crime Through Time Museum at Littledean Jail, near Cinderford, Gloucestershire, opened at the weekend.
Museum owner Andy Jones said the photographs were no different to images already available on the internet.
Some local people have criticised the opening of the exhibition as in "poor taste".
Mr Jones said: "We touch on subjects that are very taboo and hard hitting.
"We put across graphic and horrific material that no other tourist attraction would dare cover.
"It's a very controversial museum, it's not suitable for children.
"There are appropriate warning signs; if you don't want to see the content, then don't come in."
He added: "[People] should aim their anger at the authorities that allow this graphic material to be put out there on the internet in the first place."
Local resident Beth Taylor, from Berry Hill, said: "I don't think it's in the best of taste. Nobody wants to see those awful [images] of what is actually going on."
However, another local, Linda Hornchurch, said it was "good to make people aware of it".
Gloucestershire Police said it was aware of the exhibition but had received no complaints about it.
A spokesman said: "To our knowledge the owner has not placed any material about the exhibition on social media, and there does not appear to be any requirement for police investigation."
The display was described as "shocking" and "graphic" when it was revealed by the Gloucester Citizen.
The museum, which is housed in the former Littledean Jail building, displays other controversial crime-related items, including Ku Klux Klan costumes and Nazi memorabilia.
A museum has defended a decision to exhibit graphic images of beheadings by the Islamic State (IS) militant group.