Debuting on the latest episode of Collider's Heroes, the photo appears to be another costume for the Warner Bros. production. DC Films Hub, which was also provided the image, notes that Megan Gale appears to be the only actual cast member pictured; the others are apparently stand-ins.
In addition to Cotrona as the Man of Steel and Gale as Wonder Woman, the movie would have starred Armie Hammer as Batman, Adam Brody as The Flash, Santiago Caberera as Aquaman, Hugh Keays-Byrne as Martian Manhunter and Common as Green Lantern. In addition to the Justice League, the film was intended to star Jay Baruchel as Maxwell Lord, Teresa Palmer as Talia al Ghul and Anton Yelchin as Wally West.
However, Warner Bros. shelved the project on the eve of production in January 2008, amid a writers strike, concerns about Australian tax incentives and the possibility of an actors strike. All of the primary roles were cast, costumes designed (obviously), and at least some sets were reportedly constructed at the time the studio pulled the plug on Justice League: Mortal.