There is no more natural image than that of a mother nursing her baby.
But until recently if those pictures exposed what was deemed to be "too much" of a woman's breast, they were considered offensive and removed from Facebook. In some instances, mums who posted the photos were even locked out of their accounts.
But now, thanks to a change in Facebook rules, pictures of children actively breastfeeding will no longer be banned under the nudity rule and will not be taken down.
The reverse of the ban follows pressure from women around the world who were angered at being unable to share treasured photos of their baby feeding with family and friends. One group 'Hey Facebook, breastfeeding is not obscene' has almost 10,000 members while another 'FB vs Breastfeeding' has almost 9,000 likes.
But despite the vocal opposition to the ban on breastfeeding photos which exposed a woman's breast, Facebook chiefs changed the rules quietly and without fanfare last month. It was revealed instead by #FreeTheNipple activist Soraya Chemaly this week.
"Two weeks ago, if a photograph of an actively breastfeeding mother with nipples exposed was shared in Facebook, that photograph would have violated the company's guidelines regarding nudity and obscenity and been removed," Chemaly wrote in an article on US website Huffington Post earlier this week.
"According to my conversations with Facebook spokespeople, as the result of a quiet policy change made two weeks ago, that is no longer the case. The female nipple ban no longer exists for breastfeeding mothers, which should make many people who have been pushing the company to address a nudity double standard at least partially happy."
A statement on Facebook says the social media giant is "glad" mothers want to share their pictures.
"We agree that breastfeeding is natural and beautiful and we're glad to know that it's important for mothers to share their experiences with others on Facebook. The vast majority of these photos are compliant with our policies," the statement reads.
Before the rule change was made about three weeks ago, the above statement also included the words: "photos that show a fully exposed breast where the child is not actively engaged in nursing do violate the Facebook Terms."
The change will no doubt be welcomed by breastfeeding mums who want to be free to post pictures of themselves nourishing and bonding with their baby. However some people are waiting to see whether the new rules actually result in a real change in attitude towards breastfeeding mothers and babies on Facebook.
"I think it will take time for the policy to filter through the moderation process. Moderators need training, and the people who report photos need 'educating'," organisers of social project Bare Reality wrote on FB vs Breastfeeding page. "It's an important step in the right direction though, and at least breastfeeding mothers can challenge a decision to pull their photos."
Facebook's spokesman Matt Steinfeld told Chemaly the organisation's Community Standards were designed to create a "safe and respectful environment".
"We regularly review our Community Standards to ensure they're balancing the varying interests of the people who use Facebook," he said. "These interests are particularly diverse when it comes to nudity, which is why we gather feedback from people and organizations who use Facebook."
With these changes in place, more women may feel free to join movements to #normalisebreastfeeding, not just on Instagram but on Facebook as well.