Samm Newman, 19, was upset to discover that an image she uploaded showing herself wearing a white bra and polka dot briefs was removed.
Hours later, the size 24 student found that her entire account had been deleted for "violating community guidelines" - despite the fact Instagram is full of accounts posting bikini snaps and provocative images of 'thinner women'.
Speaking with NBC News, Samm has revealed she is now on a mission to challenge the way social media looks at body image.
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She said: “I didn’t find [the briefs] or the bra at all inappropriate.
“They covered me entirely and I’ve seen pictures like that all over Instagram.”
Speaking openly, Samm admitted to the US news site that she used to self-harm and was bullied and body-shamed all through junior high and high school. Her self confidence was at an all-time low.
But after taking part in a body confidence movement on Instagram, Samm became an entirely different person. Using hash tags like #bodylove and #pizzasister4lyfe, she followed a group of similarly-minded ladies, posting pictures and compliments.
She said: "My Instagram, it was my safe place because when I was there, I could share anything."
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Her account, which had 500 followers at the time it was suspended, was flagged as 'inappropriate' by other users - and taken down by instagram as a result.
She said: “Fat is not a bad word.
“How confident can you be if you keep censoring yourself because people don't want to look at you?”
Since taking a stand against Instagram and “making a huge ruckus” about the decision to suspend her account, Samm said people had thanked her for inspiring them to “feel strong and courageous and ready to fight like I have”.
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After vowing to "make a difference in the world" and making national news in the US, Samm has since received a full apology from Instagram - and had her account reinstated.
They said: "When our team processes reports from other members of the Instagram community, we occasionally make a mistake. In this case, we wrongly removed content and worked to rectify the error as soon as we were notified. We apologise for any inconvenience."
Do you think it's fair that social media users can decide what content is inappropriate?