Google Inc is preparing to roll out a service to let consumers store photos and other content online, a source familiar with the matter said, pushing into a market now dominated by the likes of Dropbox and Box.

The service, to be called Google Drive, could be announced as soon as Tuesday and would be offered with both free and premium for-pay versions, the source said.

Google's "cloud storage" offering will incorporate search capabilities and allow users to store pictures, notes and other documents on the Internet and access them from any Web-connected device.

Consumers will get 5 Gigabytes of storage for free with Google Drive, while various versions with incrementally more storage capacity, topping out at about 100 Gibabytes, will be available for monthly fees, the source said.

It was not immediately clear how much Google will charge for the premium versions.

A Google spokeswoman said the company does not comment on rumor or speculation.

The move turns up the competitive heat with high-profile Web startups such as Dropbox, Box and Evernote, as well as with Microsoft Corp and its SkyDrive service.

Some of those services, such as Box, have offered an increasing array of business-oriented features such as online collaboration capabilities.

Google is increasingly developing services to let consumers store their personal information, from digital music to photos, on remote Internet servers and access the data any time with any device, such as smartphones, tablets and desktop computers.

The world's No.1 Web search engine with roughly $38 billion in 2011 revenue, Google generates 96 percent of its revenue from advertising, such as the small ads that appear alongside its search results.

Google Drive will work with sophisticated image search technology to let consumers sift through a wide variety of document types, which could include the likes of Adobe PDF files and photographs, the source said.

Some details of Google Drive have appeared in various online blogs in recent months, including The Next Web, which first reported that the service could be rolled out this week.

(Reporting By Alexei Oreskovic; Editing by Edmund Klamann)