Earlier saw WB release a new high-res Justice League image that featured Ezra Miller as The Flash wearing his armored suit, which a lot of people aren't too thrilled about.
I say give it a chance as the Justice League Flash will have more than one suit. I believe the earlier Justice League set reports mentioned a different Flash costume than the armored version, and there is also that Flash concept art from the featurette special that aired a while back (see below) revealing a seemingly smoother Flash costume design.
The latest about the Flash costumes (thought to be two) comes via Twitter from a costume designer that worked on Justice League, Hannah Marie, aka Cotton Bun, as Hannah posted she received a gift for working on Justice League. Hannah then answered a few fan questions in the replies offering that fans won't be disappointed when asked how is the second costume of The Flash. Hannah also revealed her favorite costume in Justice League is The Flash as well.
The Flash concept art featuring smoother looking costume:
"Justice League" has a November 17, 2017 release directed by Zack Snyder starring Ben Affleck as Batman, Henry Cavill as Superman, Gal Gadot as Wonder Woman, Jason Momoa as Aquaman, Ezra Miller as The Flash, Ray Fisher as Cyborg, J.K. Simmons as Commissioner Gordon and Willem Dafoe an Atlantean, Nuidis Vulko.
Fueled by his restored faith in humanity and inspired by Superman’s selfless act, Bruce Wayne enlists the help of his newfound ally, Diana Prince, to face an even greater enemy. Together, Batman and Wonder Woman work quickly to find and recruit a team of metahumans to stand against this newly awakened threat. But despite the formation of this unprecedented league of heroes—Batman, Wonder Woman, Aquaman, Cyborg and The Flash—it may already be too late to save the planet from an assault of catastrophic proportions.