Mobile messaging app Kik is giving users new controls to protect against unwanted anonymous advances, the company said today. The app will censor images from strangers to limit lewd content being shared by surprise, explained Heather Galt, Kik’s head of marketing and safety.

“If you haven’t talked to someone before, we’re treating new conversations differently,” Galt said. “It felt like the logical next step.”

The app will blur all photos in messages when users who never interacted before contact each other for the first time. Users can only share unblurred images after they have both approved each other.

Kik, based in Ontario, Canada, is approaching 150 million registered users, many of them teenagers, Galt said. Young people—sometimes those too young for their own phones—use Kik mobile devices like iPods, because it doesn’t require a number to join.

Smartphone users like the app because it gives them a way to connect without handing over their numbers. Galt said that many users post their Kik contact info elsewhere online from Tumblr to Instagram so people they meet can message them.

“One of the biggest drivers for the app is that you should feel comfortable sharing your Kik username wherever you want,” Galt said. “That’s one of the benefits.”

However, revealing your Kik contact online means that strangers could send unsafe and explicit messages. Harassment and security concerns, always a part of the online community, have become heightened in the messaging space with the rise of apps like Snapchat, Line, Tango, WeChat and others.

Galt did not reveal how many daily users Kik has, but she said 50 percent of Kik’s daily users share photos. Kik also is combating spam on the platform, Galt said.

Brands have been waking up to mobile apps that introduce them to users. Today, Tango announced it would support brand channels for users to follow. Kik has opened its platform for brands and publishers to create mobile websites within the platform.