Rows over what photographs Facebook will permit on its vast social network are nothing new: its no-nudity picture policy has caused controversy before due its less than subtle approach.

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Apart from the deletion of the Pulitzer-prize winning photograph of a napalm attack in southern Vietnam, images of breastfeeding are frequently removed. In 2008, the company banned and removed any such images that showed nipples, causing a backlash and protests from tens of thousands of mothers.

The company’s image censorship guidelines were leaked to the press in 2012. They specifically called for reviewers to remove images of breastfeeding if the nipples were exposed but to allow “graphic images” of animals if shown in the “context of food processing or hunting as it occurs in nature”, resulting in further outcries. The company clarified its guidelines on nudity in 2015, but has not changed its policy.

Facebook says its policies are aimed at stopping pornography and abuse. The latter is a serious problem on some social media – in the UK earlier this week the director of public prosecutions, Alison Saunders, said prosecutions relating to stalking and harassment were at record levels in England and Wales because so much was being conducted online.

Facebook says it uses both automated systems and human reviewers before taking action. Users of the social network are encouraged to actively report, via onsite tools, images they think could contravene Facebook’s “community standards”.

An automated system collates those reports and flags images to human reviewers who determine if they breach the site’s guidelines, which specifically outlaw nudity.

Facebook says: “We restrict the display of nudity because some audiences within our global community may be sensitive to this type of content – particularly because of their cultural background or age.

“We remove photographs of people displaying genitals or focusing in on fully exposed buttocks. We also restrict some images of female breasts if they include the nipple, but we always allow photos of women actively engaged in breastfeeding or showing breasts with post-mastectomy scarring.”

Should content be found to contravene Facebook’s rules, it is deleted and accounts can be banned or removed. The company says the biggest problem is that for reasons of fairness and speed “it is essential that we have policies in place that our global teams can apply uniformly and easily when reviewing content”. That means one global guideline for all, regardless of local sensibilities.

Exceptions should obviously be made in some circumstances, but Facebook’s problem is when and where those one-offs should be considered and how not to allow, in its eyes, undesirable content through.

Zuckerberg continues to claim that Facebook is not a media company, just a technology company. But it is one with arguably more power than any other organisation on the planet for influencing the news agenda through promotion or censorship.