Washington, Lincoln, or the Queen, due to currency. Maybe Mao for similar reasons.
I tell you what - it's the face of the most advertised person. Currency is not used for advertising.
So out of three, it's easiest to recollect Lincoln with stove top with US flag and pointing finger. Her majesty comes second because all the memes of her longevity.
The most recognisable? Certain Hollywood actors. Period.
I would guess the “Mona Lisa”. Or maybe actors in popular films like Robert Downey Jr.
How are those gonna do inside that surprisingly-small circle you can draw over Asia and Oceania that contains half the world's population? How about all of Africa?
Whichever face it is, it's probably recognizable to both Indians and Chinese people.
I wouldn't be surprised the winner's a well-known bodhisattva. Though that opens up the question of whether it has to be a photo, and if not, the Lisa Gherardini might be a real contender (though possibly disqualified, since that identification isn't 100% certain).
Maybe I've read too many articles about US currency being used across the world. That said, I've seen a surprising amount of foreign programs reference Lincoln's image. Considering there are hundreds of billions of pennies in existence I suspect he's more well known than you'd think, even though they primarily are in the US.