On Christmas Day, the first lady shared an old photo of herself and her husband. He’s rocking a sweater vest, she’s in wide stripes. The young couple is embracing in front of a small Christmas tree, classic 1990s style on display for a throwback Thursday pic that was liked by 110,000 people on Instagram and retweeted by 18,000.

In October, she popped up on Vine, turnip in hand, nodding her head to Lil’ Jon, punning her way through a message on healthy eating that got more than 39 million views.

Our prayers are with the missing Nigerian girls and their families. It's time to #BringBackOurGirls. -mo

A post shared by Michelle Obama (archived) (@michelleobama44) on

And on a more somber note, eight months ago, she added her voice to the #bringbackourgirls hashtag activism around the Boko Haram kidnappings in Nigeria.

Michelle Obama knows her way around social media. She is a savvy digital citizen who has carefully curated her image.

But Obama’s biggest test on the medium is one faced by parents across the globe: keeping her teenagers in check as they develop their own online personas. Digital parenting, as it’s become known, is hard enough — add first daughter celebrity to the mix, and the challenge is daunting. The first lady’s approach came into focus last week after a rare and seemingly private photo of her oldest daughter, Malia, became public on Instagram.

Compared to other first ladies, Obama “has had to be more intensive about her parenting — and while the nature of this is certainly changing as they mature into their teenage years, it can’t be any less vigilant because of the particular vulnerability faced by teenagers, especially girls,” said Carl Sferrazza Anthony, historian of the National First Ladies Library.

Malia Obama rocking that classic Pro Era tee! | Make sure you get your official Pro Era gear from theproera.com!

A post shared by Official Pro Era Instagram (@proerarecords) on

In the Instagram photo of Malia, which was widely circulated online, she is posing with her hands behind her head, wearing a wrinkled T-shirt emblazoned with the emblem of Brooklyn rap group Pro Era. It’s not clear who took the photo or whether Malia intended for it to be made public. Representatives of the rap group, who quickly used her photo to promote its work, have said the photo was shared with them by a mutual friend of the first daughter who has connections to Pro Era.

The White House has had no comment on the picture, but it seemed to be a break from the publicly stated rules the first lady has laid out for her daughters. She has been a proponent of boundary setting when it comes to children and screens. When the girls were younger, she refused to let them watch television during the week. She forbid them from having smartphones before age 12, and has stated that she’s “not a fan” of Facebook for teenagers.

“We’re all trying to figure it out,” said family technology writer Jeana Tahnk, who relates to Obama’s effort to wrangle in the impact of social media on her children. “The technology is always changing. And all teenagers go through periods where they are testing boundaries and testing limits.”

Michelle Obama came onto Twitter in the course of the 2012 presidential campaign as @MichelleObama and, after the campaign, transitioned to @FLOTUS, her official White House Twitter account, which has 1.46 million followers. Her Instagram page has nearly as many.

The social media accounts are managed by the administration’s Office of Digital Strategy, which operates out of the Eisenhower Executive Office Building, and helps the administration, including the first lady’s team, tweak tweets and come up with other material likely to find a large audience online.

Obama, who signs personal messages with her initials, has been an active participant in building her online profile. She has fun with her posts, said Laura Olin, who was social media director of the Obama 2012 campaign and part of the team that started Michelle Obama’s first Twitter account.

In the healthy eating video the first lady taped dancing with a turnip to the beat of the hit Lil’ Jon song “Turn Down for What,” “she owned it and made it work by just being so game for anything,” Olin said.

The first lady has also seemed game for almost anything on her late-night TV appearances, which in turn go viral. “The Evolution of Mom Dancing” with Jimmy Fallon — gentle mockery of how embarrassing moms can be, in service of promoting healthy eating — has been viewed on YouTube 20.6 million times since it aired in February 2013.

Obama may be comfortable and careful crafting her own persona, but raises a barrier to that authenticity when it comes to her children. The Obamas have been circumspect regarding their daughters’ private lives — telling stories about them in generalities and sharing poised, professional photographs of the family with the world.

The tension over the images of children in the White House isn’t new — though it is surely more intense and amplified by social media. Anthony, the historian of first ladies, noted that their lives are a topic of constant national interest and their media depictions have long been closely monitored by first ladies.

In the early 1900s, Edith Roosevelt — the wife of President Theodore Roosevelt — famously refused to sit for interviews with reporters, but allowed her rambunctious children, along with their pets, to pose for photographs that were distributed to magazines and newspapers. The portraits satisfied the public’s interest in the children’s lives.

Malia and Sasha are similarly photographed. They are present for holiday celebrations and, on occasion, at diplomatic gatherings, such as when Michelle Obama and her mother were greeted by Chinese President Xi Jinping during a trip there last spring. On a brisk schedule for a week in March, they were briefly visible to reporters during portions of the first lady’s tours of China’s landmarks.

During that same visit, the first lady posted online a photo of herself and her daughters embracing lovingly on the Great Wall. Obama captioned the post, “Sharing a moment at the Great Wall.” The photo, which was taken by an official White House photographer out of view of news reporters, garnered 63,000 Instagram likes.

“They do walk the line of giving people a sense of who they are as people, which is a really important part of relating to a public figure, and also keeping their private lives private,” Olin said. “They seem to be very careful about how much Malia and Sasha are a part of the communications.”

Malia and Sasha Obama are special cases, of course, but they’re also in many ways like other kids born in the late 1990s and early 2000s — whose peak adorability was chronicled in digital photos, and, soon enough, posted by their parents online. According to a 2010 study by Internet security firm AVG, 34 percent of parents in the United States post their sonograms online and 92 percent of mothers in this country have uploaded images of their children before the age of 2.

When those same children become pre-teens, “there is a little bit of irony perhaps the parents can post pictures about their children but the children don’t yet have that right,” said Sarita Schoenebeck, an assistant professor in the School of Information at the University of Michigan, where she studies trends among families on the Internet.

The same is true for Obama’s daughters whose public online personas have largely been shaped by others. Before her daughters became teens, Obama said she warned them of the ways social media could shape their images.

“I think they are [some] of the first kids in the White House growing up where everybody’s got a cell phone and everybody’s watching,” the first lady told the women’s Web site iVillage in a 2012 interview. “We just have to have real conversations even now, it’s: ‘You can’t go off on somebody. You can’t act bratty. You may be having a moment but somebody could use that moment and try to define you forever.’”

Obama knows firsthand that the Internet can be a volatile space. She is a popular figure but has still been the target of snarky comments and the recipient of crude posts from anonymous Internet commenters.

Children, especially famous ones, are not exempt from such treatment. Just last month, Elizabeth Lauten, the communications director for Rep. Stephen Fincher (R-Tenn.), resigned after she wrote a post on Facebook criticizing the appearance of Malia and Sasha at the annual White House turkey pardoning ceremony.

The reason the photo on Instagram of Malia Obama caught traction online was because unpolished images of a first family’s children are unusual. “To get a glimpse of them being just regular teenagers is so rare,” said Tahnk.

For Schoenebeck, the unexpected photo seemed to provide a “nice teachable moment” and reminder of the influence that comes with living in the White House — even as a teenager.

It’s a key time for such a reminder. Soon the president and first lady’s daughters will be adults with a freer hand shaping their own Internet profiles.

“I’m excited to see how they decide to come online as they gain independence,” Schoenebeck said.

Someday, their Instagram fan-base could rival their mother’s following.