DALLAS, GA. -- A total of nine students and staff members at a Georgia high school have tested positive for the coronavirus, the principal said in a letter to parents after the school made headlines for online photos showing hallways packed with teens -- many of them not wearing masks.

Principal Gabe Carmona wrote Saturday that six students and three staff members at North Paulding High School west of Atlanta tested positive for COVID-19. The Atlanta Journal-Constitution reported it obtained the principal's letter from a spokesman for the Paulding County School District.

The infected students and staff members were inside the school building "sometime" last week, Carmona's letter said. He said the school was disinfecting the building, but it was unclear whether the school would quarantine other students and staff who may have been exposed.

Meanwhile, school officials in a nearby metro Atlanta county reported 12 students and two staff members across a dozen schools tested positive for the virus during their first week back at school. The Cherokee County school system reported that more than 250 students with potential exposure had been sent home to quarantine for two weeks.

"We have students and staff reporting presumptive, pending and positive COVID-19 tests every day, and this will continue as we operate schools during a pandemic," Cherokee County Schools Superintendent Brian Hightower wrote in a letter to parents Friday.

Cherokee County also drew attention because of online photos. Dozens of students at two of its high schools squeezed together for first-day-of-school senior photos. None wore masks.

Hightower said in his letter that many of the seniors in those online photos "wear masks routinely" -- though the schools don't require them to. He also said the school system was taking "extra steps for transparency." In addition to the superintendent's letter, the school system posted information about all confirmed infections and quarantines on its website.

North Paulding High School made headlines last week after photos posted on social media showed crowded hallways and some maskless faces.

Paulding County Superintendent Brian Ottot said photos of the crowded hallways were accurate, but also said the district is following state guidelines and that students need longer than a few minutes in the hall to catch the virus from others.

Ottot defended the district's decision not to require masks. He wrote that wearing a mask "is a personal choice and there is no practical way to enforce a mandate to wear them."

North Paulding student Hannah Watters was suspended last week for taking a photo and video of the school and sharing them with news organizations. The suspension was dropped on Friday.

Paulding County's 30,000 students were offered a remote learning option. About 30% of students chose online learning. Cherokee County school officials said 22% of the district's 42,200 students opted to start the year with online classes.