The image is a work-in-progress cover that will be used for "Road to the Avengers," which is a movie tie-in comic. Judging by the shot, Captain America will be the leader of the group, something that Hemsworth recently confirmed in an interview. Check out the cover below.
Joss Whedon (Serenity) is currently shooting "The Avengers," which is set to hit theaters on May 4th, 2012.
Source: Worst Previews