A Washington state high school teacher has resigned after explicit images were briefly displayed to students during a classroom presentation.

According to a letter sent home by Glacier Peak High School principal Alicia Mitchell obtained by KING 5 News, the incident occurred on Wednesday when a teacher inadvertently showed four images depicting a woman’s bare breasts while presenting a PowerPoint to students.

“We want to make you aware of an incident in a classroom where inappropriate images were inadvertently shared with the students,” Mitchell wrote. “It is our understanding that these images have since been viewed by many others beyond the classroom, and want to give you an opportunity to process with your student if you choose to do so.”

Mitchell said the images were “briefly visible” and appeared in small preview-style boxes on one of the slides. She emphasized that the material does not reflect the school’s standards and confirmed that the situation prompted an investigation.

“The content included images of nude breasts and were briefly visible during a teacher’s PowerPoint presentation,” she added, noting that the incident is not aligned with the school’s “expectations for classroom materials.”

Following the incident, the teacher resigned. It remains unclear whether the images depicted the educator or another individual.