In addition to uploading those photos from Christmas Day and last night’s bar excursion, Flickr users can now use the popular photo-sharing Web site to view images from the Library of Congress’ vast collection.

On Wednesday, Flickr became the host to thousands of historical pictures from the Library, ranging from a newspaper’s daily photographs to portraits of World War II Marines.

It’s the Library’s latest attempt to engage the public through the Internet. Hopefully, it will be a two-way street, said spokesman Matt Raymond: Flickr users will be able to view and discuss the photos, and the Library might learn more about the photos’ origins through users’ comments.

“Part of the reason for this is to learn how it might help us,” Raymond said, adding that one expected advantage is getting “some of the unique collections of the Library’s photo collection out to the broadest possible audience.”

The partnership between the Library and Flickr also has provided more opportunities for other organizations and museums that have similar collections. Unlike individual users of Flickr, the Library is able to put its photos into the public domain — an option never before considered.

So far, Flickr only offers this option to the Library, but the company hopes to work with other groups in the future, said George Oates, a Flickr senior program manager. Many museums and cultural institutions already are looking for a way to extend the reach of their materials, she said.

“For a very long time, Flickr has been about user-generated content,” she said. But adding a public domain function, she added, “makes it all the richer.”

About 3,000 Library photos have been put on the site so far, and all have no known copyright protections. They come from the Library’s two most popular collections: photos from the Bain News Service and work done by photographers working for the U.S. Farm Security Administration during the Depression.

But it’s a small slice of the 14 million photos, prints and other visual materials in the Library of Congress. While a chunk of that is already available on the Library’s Web site, Flickr has developed technology to allow users to discuss, sort and find photos easily, Raymond said. By catching the public’s interest on popular sites, the Library can reel people into its own Web site and gain more interest.

Eventually, the Library might add more unique collections to the Flickr site, Raymond said.

“You wouldn’t believe the interest in some of the esoteric,” he said. “There are millions of people interested in these types of resources.”