As military leaders scramble to track down those involved in publishing the photos, new details emerged about further proscribed online activity.
The investigation has now expanded to at least a dozen spinoff pages that posted the lewd images, and the Navy is now looking at the possibility that those involved in the activity included sailors from aircraft carriers and at major naval bases, a Navy official said.
Marine Corps Commandant Gen. Robert Neller signed the new social media guidelines in order to clarify that the military code of justice punishments that apply to social media sexual harassment are the same as those that apply to all other forms of sexual harassment.
"Marines must never engage in commentary or publish content on social networking platforms or through other forms of communication that harm good order and discipline or that bring discredit upon themselves, their unit, or the Marine Corps," the guidelines state.
Under the new guidelines, a Marine who posts online commentary and content that is defamatory, threatening, harassing or discriminatory can be punished at the discretion of a military court.
Defense officials have said that this scandal has raised questions about whether the Uniform Code of Military Justice is sufficient to deal with cyber issues, a point that was echoed on several occasions during a hearing before the Senate Armed Services Committee on Tuesday.
In his testimony, Neller condemned those who posted the photos to private Facebook groups, like Marines United and other image-sharing message boards, without the consent of the subjects.
He also reiterated his commitment to identifying underlying issues in military culture to determine why this happened and whether new service members understood that such behavior is not acceptable.
But lawmakers and service members rights groups are demanding answers and action in the wake of a scandal that many say reflects poor leadership from military brass.
New York Democratic Sen. Kirsten Gillibrand tore into Neller during the hearing, calling his testimony "unsatisfactory," and demanding to know why nothing had been done to hold individuals accountable for the online harassment of women even though reports date back to 2013.
The ACLU also demanded accountability from the Marine Corps on Wednesday.
"There is little doubt that this crisis is the result of significant cultural problems within the Marine Corps and a failure of leadership at the highest levels," Faiz Shakir, ACLU national political director, said in a written statement.
Some lawmakers, however, have defended Neller.
California Republican Rep. Duncan Hunter blasted Gillibrand's grilling of Neller during Tuesday's hearing and voiced his support for the top Marine in the wake of the scandal.
"This commandant is like his predecessors in so many ways, especially when it comes to caring for his Marines and ensuring they're the most effective fighting force in the world," Hunter said in an op-ed for Fox News
"But he has his own distinct qualities and attributes, and it's safe to say that no commandant has ever rivaled his dedication to the creation of a diverse Marine Corps," Hunter said.