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They say a picture is worth a thousand words. For the social photo startup Imgur, however, you might bump that up a few more figures.

The site announced on Thursday it had raised a $40 million round of venture funding, the first time the company has raised significant outside capital since its founding in 2009. The round was led by Andreessen Horowitz, and general partner Lars Dalgaard will take a seat on Imgur’s board.

Imgur may not be a household name in social at this point. For years, the site has been largely known as an online hosting service of sorts, a repository for people to upload photos and then share out to other services like Facebook, Twitter or the wildly popular link sharing community site Reddit.

But in just a few years, it has grown from founder Alan Schaaf’s pet college project to a Web traffic phenom, attracting upward of 130 million unique visitors to the site on a monthly basis.

Much of that growth came from the company’s tight affiliation with Reddit in Imgur’s early days; Schaaf built Imgur because he wasn’t satisfied with other services that hosted photos he wanted to post quickly and simply online. Reddit loved Imgur, and the site’s popularity soared.

But for some time, Schaaf and COO Matt Strader have aimed to turn Imgur into a destination site of its own — a social network of sorts, or the “YouTube for images,” as Schaaf so fondly refers to it.

That is to say, Imgur doesn’t want its biggest traffic referral assets — like Facebook and Reddit — to become liabilities if Facebook’s algorithms or Reddit’s user sentiment shifts suddenly, thereby making the traffic fire hose run dry.

“There are tons of companies built off the Facebook News Feed,” Schaaf said in an interview. “I can guarantee you Imgur is not that.”

Currently, Schaaf said more than 30 percent of Imgur’s traffic comes in through the front door. Traffic from Reddit, then Facebook, and a handful of other sites like Pinterest and Twitter, follow shortly thereafter.

“We’ve never been overly reliant on one source, and we’ve currently got very distributed traffic,” COO Strader said.

That said, Reddit is certainly important to the company. The site remains Imgur’s largest indirect source of referral traffic, and even participated in Imgur’s round of venture funding, joining Andreessen Horowitz and others in contributing.

Schaaf said the funding will be used to aggressively hire engineering resources on iOS, Android and the mobile Web, and he also plans to build a sales team.