It's funny, but one of the definitions on dictionary.com says:
often hard·core (härdkôr, -kr) A form of exceptionally harsh punk rock.
But like Lab, I immediately thought of porn. For me the terms "soft core" and "hard core" related to a level of sexual explicitness, so when I saw this thread, I figured the image would be of something of a sexual nature. I guess I'm an old fogie like Lab.
Lynn