Social media giant Facebook is reviewing its nudity policy after the Montreal Museum of Fine Arts complained the site kept blocking its ads for a Picasso exhibit.

The museum initially used an image of the artist's 1956 painting Femmes à la toilette — a cubist work that features two naked women — to advertise an ongoing show called From Africa to the Americas: Face-to-Face Picasso, Past and Present.

But when the museum tried to circulate the ad on Facebook, it was rejected because of the site's anti-nudity policy.

"It was funny for us, you know, like unbelievable," ​Pascale Chassé, a museum spokesperson, told CBC Montreal's Daybreak.

Picasso's 1956 painting, Femmes à la toilette, triggered Facebook's algorithm to flag it as inappropriate content. (CBC)

The museum changed the ad three times using different images from the exhibit, though each contained at least one breast. All of those were rejected too, Chassé said.

Facebook even rejected a gallery photo that had one of the offending nude paintings in the background.

"It's ridiculous. It's Picasso," Chassé said.

Fed up, the museum appealed to Facebook directly, asking that photos of internationally renowned high art be allowed.

In response, Facebook agreed to let the museum's ad live online. The social network site is now also considering extending that exemptions to others as well.

"We want to make sure that museums and other institutions are able to share some of their most iconic paintings," said a Facebook spokesperson in an email.

Visitors to the exhibition got to see some of the artwork originally deemed inappropriate by the social media giant first-hand. (CBC)

The statement also said: "Nudity in paintings is currently not allowed in ads.… [We are] currently reviewing our approach to nudity in paintings in ads on Facebook."

Chassé believes it was Facebook's powerful algorithms that flagged the museum's ads as inappropriate content.

She said that once they complained, a human analyst was assigned to take a look at the flagged content.

"You just have to talk to a human," she said. "First it's algorithm. If you want to protest or have more explanation, it has to go to a human."

She said she's happy, and surprised, that Facebook was willing to play ball and consider revising their approach. And if it helps other museums in the quest to get visitors through the doors, then that's all the better said Chassé.

With files from CBC Montreal's Daybreak, Matt D'Amours