Facebook, which is one of the world's largest photo-sharing sites (in addition to being the leader among social networks), is rolling out some marked improvements to its Photos product.

These upgrades include hi-res photos, photo-download links, bulk tagging options and an elegant lightbox interface for viewing images from anywhere on the site. The lightbox in particular reminds us of similar features recently rolled out by Flickr; and some of these improvements, such as hi-res and downloading capabilities, are what have prevented Facebook from serious competition with Flickr as a photo-sharing destination.

In the recent past, Facebook photos were best for capturing memories of places, people and events through small images and mobile snapshots; however, these changes allow a whole new class of image-sharing, up to and including photography, modeling and graphic design portfolios. With its 500 million users around the world, Facebook is now poised to take over the photo-sharing market.

Beginning today and rolling out to all users soon, you will be able to upload and download hi-res photos up to 2048 pixels wide or high — that's large enough for print-quality images. (Currently, Facebook only displays 720 pixels; larger photos simply get resized.) Each photo will come with a link to download the JPEG file, as well.

The site's new bulk tagging options will allow the uploading individual to temporarily group images and tag friends by simply clicking on thumbnails.

Another interesting change is Facebook's lightbox UI, which strongly and clearly puts the focus on images. Starting soon, any time you click on an image anywhere on Facebook, be it in an album or in your News Feed or on a friend's Wall, you'll see a black box hovering over the rest of the screen with some minimal navigation controls and relevant social features, allowing you to concentrate completely on the image at hand.

While we don't love the ads in place here, we do realize that hosting hi-res photos costs a lot more and will attract a lot more usage — both from uploading parties and from viewing individuals — all of which puts more strain on Facebook's servers. We'll sacrifice an ad-free experience for higher quality photos.

What do you think about these changes? Do you think Facebook — which already competes with Twitter as a status service, Google as an advertiser, and every major social network as a digital hub for friends — will soon be competing with Flickr for the photos of pros and amateurs alike?