With a single click, the feature will allow users to wirelessly upload high-resolution pictures straight from their smartphones onto the virtual "cloud," where the files can be accessed from any computer or mobile device.

Dropbox only offers users storage space - the service will not provide any photo editing or manipulation features, like those provided by Google's Picasa program.

Instead, CEO Drew Houston said, the company hopes that third-party developers will step in and do precisely that.

Houston said the new development represented a small but significant step toward cultivating a thriving "ecosystem" around the Dropbox platform. In the case of photos, for example, the company will encourage independent developers to write programs to touch up photos.

"Facebook tied your friends and your social graph into this ecosystem that offered all these services," Houston said. "We envision similar things with Dropbox."

He added: "It's a major theme for us going forward this year."

Although the first release of the app will only be available for Android phones, an Apple iOS version will be released shortly, the company said. Users get 500 megabytes of storage after their first upload and can receive up to a total of 3 gigabytes of extra free space.

Dropbox's new app, which targets a huge consumer demand for photo-sharing, was meant to "secure and solidify their position as the best file-sharing service and trying not go beyond that, which I think is a smart move." said James Staten, an analyst at Forrester Research.

With 100 employees in San Francisco and 50 million users, Dropbox is one of the most closely-watched startups by Silicon Valley investors - and its much larger competitors.

Earlier this month, Google announced Drive, a cloud storage service that was seen as a direct answer to Dropbox's dramatic recent growth.

Similarly in June, Apple announced iCloud, a consumer-oriented service for Apple users that also syncs email and calendars.

And Microsoft has also recently pushed to expand its cloud offerings for enterprise computing.

Founded by Houston and a classmate from the Massachusetts Institute of Technology in 2007, Dropbox has raised $250 million at a reported $4 billion valuation.

(Reporting By Gerry Shih. Editing by Mark Potter)

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