The poster is an homage to Alex Ross, who has done the artwork for many DC comics, and that one on the comic cover was done by him. This article shows that there are many comparisons, and confirms that the photographer did base the poster off of his work.
According to Clay Enos, the photographer for the movie poster:
“I first saw this painting as part of the Ayman Hariri’s Impossible Collection and it inspired me to shoot our gang in the same style,” Enos said, referring to Ross’s painting of the Justice League for the 2005 Justice comic book series seen below and to the DC Comics collection of a billionaire. “I used this exact image as my reference for what became the latest JL poster. I simply had the idea and took the initiative to pay homage to Alex Ross by making a few quick portraits in that distinctive light.”