This post authored by Terence Lee is cross-posted from our media partner sgentrepreneurs

Despite having an immature tech startup ecosystem, South Korea is home to some promising young mobile companies, many of which have amassed sizable traction on their apps. These next generation torch-bearers are lighting up a new path in the country,  and their fast growth marks a promising start for entrepreneurs in the well-connected and tech-savvy nation.

SGE has featured a number of these Korean startups: There’s KakaoTalk, a very promising instant messenger with over 50 million users, and Between, a private social network for couples with more than 400,000 monthly active users at last count.

JellyBus, a company that has produced a bevy of photo-related mobile apps, is another noteworthy startup. What strikes me about founder and CEO Sejoong Kim, from the time he presented on stage at Echelon 2011 as a finalist, was his unabashed mission of bringing joy and happiness to people, a mantra he repeats often.

“We know people really enjoy taking a photo for delivering (sic) their joyful moment,” he told us via email.

His good-natured philosophy, which hints at his company’s user-centric focus, has paid dividends. At this point, JellyBus has made a total of 11 photo apps for various platforms, amassing a total of 900,000 monthly active users. The feat was achieved through bootstrapping alone, said Sejoong, who started the company in 2009.

One of its newer and most promising apps is HDR FX, which  focuses on enhancing scenery photos to make it more life-like through specialized editing tools. It also has 42 filters that modifies either the sky, foreground, or the entire photo to achieve a desired effect. For instance, you can edit a photo such that it looks like it was shot in the morning or in Autumn, depending on your whims.

The app is designed for two groups: Users with little knowledge of photography but who want an easy way to enhance their scenery photos, and amateur photographers who desire more granular control when photo editing.

HDR FX appears to have hit the right formula: It has garnered over 2 million downloads and 250,000 monthly active users so far. It has a selling price of US$1.99.

Sejoong isn’t overly concerned with competition from Instagram and a bevy of competitors out there. In fact, he doesn’t really consider them competition.

“Instagram is a great friend to Jellybus,” he said, explaining that both companies are complementary by nature. He suggested that Instagram has introduced people to more photo editing possibilities on mobile phones, generating thirst for similar products.

And besides, Sejoong won’t stop at making picture taking apps. Jellybus isn’t merely a photo apps company, but rather possesses the grander mission of helping people gather cherished memories — which makes them happier of course.

As such, it is currently developing a suite of video-making apps, and by the second half of 2012, Sejoong aims to enter the smart TV market.

“JellyBus must be in people’s mind as the excellent and favorite brand, like a friend,” he said.

A technical point: HDR refers to High Dynamic Range imaging, which is a method of photography where multiple shots are taken at different exposure levels and then combined to achieve the best lighting possible. The app uses postediting tools to achieve a similar effect. It does not do HDR imaging.

This post is cross-posted from our media partner sgentrepreneurs.