(NYTIMES) - To those fearful of a future in which videos of real people are indistinguishable from computer-generated forgeries, two recent developments that attracted an audience of millions might have seemed alarming.

First, a visual effects artist worked with a Tom Cruise impersonator to create startlingly accurate videos imitating the actor. The videos, created with the help of machine learning techniques and known as deepfakes, gained millions of views on TikTok, Twitter and other social networks late last month. Then, days later, MyHeritage, a genealogy website, offered a tool to digitally animate old photographs of loved ones, creating a short, looping video in which people can be seen moving their heads and even smiling. More than 26 million images had been animated using the tool, called Deep Nostalgia, as at Monday, the company said.