Played by Paul Rudd. The image doesn’t give much away apart from he has been in some kind of fight and seems to be carrying a bag which could be from a robbery he may have just committed before he turns to the side of good.
Taken from comicbookresources.com:
“Ant-Man” officially began production this week, and in celebration, Marvel has released the first official look at star Paul Rudd as the film’s protagonist, Scott Lang. Revealed by USA Today the photo depicts Rudd in a hooded sweatshirt with the iconic Golden Gate Bridge in the background on a foggy day.