ABC News' Barbara Garcia reports:

A North Carolina high school is ending the school year with controversy thanks to a photo in the school's yearbook that is similar to the famous scene in the movie "Basic Instinct," in which actress Sharon Stone bares her … well, essentials.

The group photo was taken at Lake Norman High School 2011's graduation.  In the photo, one of the nine students is spreading her legs appeared not to be wearing any undergarments.  The photograph went largely unnoticed until the recent end-of-year publication of the school's yearbook.

Word of the photo spread like any high-school gossip would. One parent told ABC station WSOC about the photo as soon as the annual school memoir was published. 

"People were texting each other to turn to page 14," the parent said.

The girl in the photo has not been identified by the school, but district officials said they were investigating the incident and were in touch with the former student.  It was unclear if the provocative photo was a mistake or if the student intentionally orchestrated a barely-there senior prank.

School district official Dawn Creason said that the photo was not clear and the possible flash may have  been created by an optical illusion. 

"Really looking at the image, though, we're not sure that's what it is at all," Creason said.  "We think, probably, it was the way she was sitting and the angle of her gown.  We're not convinced, at all, that you're seeing what you think you are."

It's unclear how the photo made it past the yearbook staff or the faculty member that oversees the group. 

School officials stressed the student was 18 at the time the photo was taken - ruling out any child pornography charges. 

The local sheriff's office has not said what, if any, criminal charges the girl could face, and was waiting for the school district to perform its investigation  before launching one of its own.

The district has sent a letter to parents and has offered a refund on the $100 annual.