The Manchester tribute flag you're seeing all over the Internet was created by an artist who never signed off on his work being used by millions of people ... for free, mind you -- and yet he's not pissed.
Mark E. Tisdale, who's American, tells TMZ he created the original art back in 2013. He was surprised to see it become such a uniting symbol for the Manchester tragedy ... posted by tons of people, including David Beckham.
Mark says, obviously, he didn't design the flag years ago with tragedy in mind. However, in light of the bombing ... he's glad it's being used to help bring people together on social media.
And while his art's mostly being spread without crediting him ... he says he has gotten a lot more traffic on his website where he sells his digital art.
Mark's planning to donate any dough he makes off the Manchester flag to relief efforts.