In this image released by Disney, from left, Paul Rudd, Jeremy Renner, Chris Evans, Elizabeth Olsen and Sebastian Stan appear in a scene from "Captain America: Civil War." Evans has wrapped his final performance as Captain America. Evans tweeted Thursday, Oct. 4, 2018, that his last shooting day on "Avengers 4" was an "emotional day." The 37-year-old actor thanked his colleagues and fans for his eight years as Captain American, saying it "has been an honor." "Avengers 4" is slated to open in May next year. Disney-Marvel (courtesy)

The internet may have discovered the "Avengers 4" poster in a hidden place.

What's going on: Reddit users are investigating a photo posted by "Avengers 4" directors Joe and Anthony Russo.

The Russo brothers posted the photo last month. It showed Joe Russo sitting in a chair with a ladder in the background, seemingly on the set of the new "Avengers" film. He added the caption, "Look hard…"

Since that time, internet theorists have tried to figure out what the photo means.

Why it matters: All of the above seems like a long shot. But it is another attempt by the massive Marvel fan base to uncover details about the new film. "Avengers" fans have been examining the photo for nearly a month now, highlighting everything from the photo's ladder to the props scattered across the room, Mashable reports.

Newest news: But there is new "Avengers 4" news out there. Actor Frank Grillo, who played the Hydra agent and terrorist Crossbones in "Captain America: Civil War," will return in a flashback scene, IGN reports.

  • "He makes an appearance in the next Avengers movie," Grillo said in a UFC Unfiltered podcast, according to IGN. "But it's a flashback … I'm allowed to say whatever I want because I'm never doing another Marvel movie."

Trailer?: The first "Avengers 4" trailer is

in November since previous "Avengers" trailers have dropped around that time. However, given the nature of the "Infinity War" final scene, it's unclear if Marvel will take a different approach with its new film.