First of all — here's the brand new Justice League movie poster in Hi-Res!
At the beginning of the 2-hours Warned Bros. panel, Henry Cavill briefly took the stage with his Justice League co-stars to greet the fans and to present the new poster (see above) and the first footage (see below).
Pictures of Henry at the WB panel
After the Warner Bros. panel, Henry Cavill walked around at the convention center in a Guy Fawkes mask briefly revealing his secret identity to the Suicide Squad cast when he came to the autograph session and asked them to sign his Suicide Squad T-shirt.
Pictures of Henry asking autographs of Suicide Squad cast
And finally — the first Justice League Footage!