While we’re still waiting for Marvel to unveil an official teaser trailer for The Avengers – and not just a “button,” like the clip that showed at the conclusion of Captain America‘s end credits – the comic book/movie studio has been busy releasing lots of images, character profiles, and more to help heighten anticipation for the (hopefully) game-changing superhero ensemble adventure.

Now we have more still frames from the film, which offer an early look at several big-name characters in action – including S.H.I.E.L.D. head Nick Fury and the catsuit-clad Natalie Rushman/Natasha Romanoff/Black Widow.

It’s expected that a full-blown teaser for The Avengers will be released in the near future, providing a better look at the super-powered protagonists of the film as well as the villains, which include the devious Loki and an army of malevolent extraterrestrial invaders.

Here is a description of the Avengers movie (for those who are just tuning in):

Based on the ever-popular Marvel comic book series, first published in 1963, “Marvel’s The Avengers” brings together the mightiest super hero characters – Captain America (Chris Evans), Thor (Chris Hemsworth), Iron Man (Robert Downey Jr.), The Hulk (Mark Ruffalo), Black Widow (Scarlett Johansson), Hawkeye (Jeremy Renner) and Nick Fury (Samuel L. Jackson) –  as they all assemble together on screen for the first time to battle a new and deadly threat. The star studded cast of super heroes will be joined by Cobie Smulders (“How I Met Your Mother) as Agent Maria Hill of S.H.I.E.L.D., as well as Tom Hiddleston (“Wallander”) and Stellan Skarsgård (“Angels & Demons,” “Mamma Mia!”) who will both reprise their respective roles as Loki and Professor Erik Selvig from the upcoming Marvel Studios’ feature “Thor.”

Now check out a handful of those players in the Avengers photo gallery below:

Be sure to let us know what you’re sort of action/fight sequences you’re hoping to see in The Avengers, not to mention how the film looks so far (based on these early production stills) in the comments section below.

We’ll find out for certain how it all goes down when The Avengers arrive in U.S. theaters on May 4th, 2012.