I realize I’m a bit late with this one, but it’s a fun splash page from Uncanny X-Men #268 by Jim Lee. This has become an iconic depiction of Cap. They’ve used this image for t-shirts, posters, covers, you name it.
With the Captain America movie that just came out, they’ve even used it as a reference for some of the movie merchandise. Don’t believe me? Check out this birthday set. Clearly a homage to this image.