The photo was taken by Sakchai Lalit of the Associated Press on October 19.
It shows a crowd of thousands flashing three-finger salutes of defiance against the Prayut government at the Kaset intersection in Bang Khen district.
Time chose the image among 100 photos that defined the year 2020. Others included shots of a Covid-19 victim hugging a doctor, bush fires raging in the US and Australia, the Black Lives Matter protest, and the deadly chemical explosion in Beirut.