The Chinese app Zao, which allows users to swap their faces with movie or TV characters, has quickly become one of the country's most popular apps .
It was released on Friday and went viral, as Chinese users took the opportunity to see themselves acting out scenes from famous films, using deepfake technology , which has already raised privacy concerns
Users upload various selfies, in which they wink, move their lips, and make various facial expressions, which the app uses to realistically transform the person's image in movies, TV shows, or other content.
The company was forced to issue a statement on Sunday after critics attacked the app's privacy policy, which had "free, irrevocable, permanent and transferable" rights to all user-generated content.
There is growing concern about deepfake technology, which uses artificial intelligence to transform photos into more convincing ones. Critics say the technology could be used to create fake videos to sway election results, discredit someone or cause unrest by spreading misinformation on a massive scale.
"We understand the privacy concerns . We have received information and will fix the issues we overlooked, which will take some time," the company said.
Zao is owned by Momo Inc, a Tinder.
Following the criticism, the app changed its terms and conditions and will no longer use headshots or videos uploaded by users, except to improve the app. It also promised to remove from its servers any content that was uploaded but later deleted by users.
The privacy claims have not affected the app's popularity, however. As of Monday afternoon, it remains the top free app downloaded in China, according to App Annie.
Concerns about deepfake technology have grown since the 2016 US election campaign, which was widely used for online disinformation, according to US research.
In June, Facebook CEO Mark Zuckerbergsaid the social network was struggling to find ways to tackle deepfake videos, saying they may be a completely different category of misinformation than any it has faced so far.
