“It definitely stung a little because it was my profile picture and I’ve had it for three years now, and it’s just my face — I’m wearing a regular T-shirt that I think I got at the Gap,” Ms. Ray said. She said it had taken several days for her appeal to reach a person at Facebook. The photo was then approved, but it was too late for a contest her blog was running.

Facebook’s ad practices have long been scrutinized, even more so after 13 Russians were indicted in February on charges that they tried to disrupt the 2016 presidential election by, among other things, distributing divisive ads through the social network. But the disputes raised by Ms. Venero and Ms. Ray are indicative of questions raised by smaller advertisers, who rely on Facebook to market their work but often have to navigate the appeals process themselves.

Facebook prohibits adult content in ads, including “depictions of people in explicit or suggestive positions” and “activities that are overly suggestive or sexually provocative.” The rules also extend to “implied nudity,” “excessive visible skin” and images that are too focused on individual body parts “even if not explicitly sexual in nature.” On Facebook’s website, all of the examples showed women.

“Facebook’s policies have the effect of sexualizing women’s bodies in a way that is not necessary and very unhealthy for society,” said Jillian York, the director for international freedom of expression at the Electronic Frontier Foundation , which advocates digital privacy protections. She added that while the company allowed topless men, it took a strict approach to nudity of a female torso.

Joel Jones, Facebook’s vice president of global marketing solutions operations, said that the company tended to be “conservative” when monitoring ads that people might find offensive but that its enforcement of adult content did not distinguish between men and women. Human reviewers are trained with examples that feature both men and women, Mr. Jones said, and he noted that more women appeared in ads — almost twice as often as men in a sampling during the previous 30 days.

For advertisers, debating what constitutes “adult content” with those human reviewers can be frustrating. Goodbye Bread, an edgy online retailer for young women, said it had a heated debate with Facebook in December over the image of young woman modeling a leopard-print mesh shirt. Facebook said the picture was too suggestive.