Graphicly StoreMovies based on Green Lantern, Thor, Captain America, and the X-Men are all due out this year, but it looks like Hollywood executives aren’t the only investors taking a close look at comic books. Graphicly, a startup behind an application for buying and reading digital comics, just announced that it has raised $3 million in its first round of institutional funding.

2010 was a big year for digital comics launches, with startup ComiXology probably attracting the most attention for its Marvel and DC Comics iPad apps. But chief executive Micah Baldwin said in July that Graphicly was aiming beyond the iPad — it now has applications for Windows 7, Adobe Air, iPhone, iPad, Windows 7 Phone, Android, and the Google Chrome Web Store. And it has signed deals with publishers including Marvel, Archie Comics, IDW Publishing, and Boom Studios.

Users have downloaded the Graphicly app 600,000 times and spend an average of 20 minutes per visit, Baldwin told me yesterday. With the new funding, he plans to expand the application beyond just being a store and a reader: “Imagine clicking on a spot within a comic and launching a casual game or video that truly extends the story.”

The round was led by DFJ Mercury, with participation from 500 Startups (the “super angel” fund from well-known investor Dave McClure), Dundee VC, Ludlow Ventures, and individual angel investors. The Boulder, Colo. startup was incubated by TechStars and previously raised $1.2 million from DFJ Mercury and others.