Facebook has started a limited test of a new photo-tagging feature that blends an element from point-and-shoot digital cameras into the social networking world.

It's about time, too, for any mass-photo-uploader on Facebook knows just how long it can take to run though every uploaded shot to tag one's friends in the picture.

Here's what we mean. While Facebook does allow other users to tag themselves in a person's shots, the procedure for doing so is still fully manual: You click on an area of the photograph you want to tag, select a name from your entire list of friends, save the tag, and repeat the process.

Or, at least, that was the old way to do it. Facebook's new feature—which has yet to roll out to the site's entire audience—is a built-in face recognition system for pictures uploaded to the site.

Facebook won't automatically tag your friends for you per se. However, users included in the trial will find that the faces of people in their photos are automatically selected alongside a prompt that asks the user, quite simply, "Whose face is this?"

"With this new feature, tagging is faster since you don't need to select a face. It's already selected for you, just like those rectangles you see around your friends' faces when you take a photo with a modern digital camera," writes Sam Odio, Facebook's product manager for Photos. "All that's left for you to do is type a name and hit enter. Cool, huh?"

According to Odio, more than 100 million photographs are uploaded to Facebook each day. That's quite a bit of tagging. Unfortunately, there's been no indication by Facebook as to when the trial period might end for its new auto-discovery feature or, for that matter, when said technology could roll out to Facebook as a whole.

However, Odio says that this is just the first of many improvements for browsing, uploading, and tagging Facebook photos. Stay tuned... and tagged!