Like many of us do, Jay Breen posts snapshots of his life on Facebook.

"If I'm doing something interesting or fun, like traveling, traveling to other countries or you know, to an island," he explained.

But when a friend of his mentioned seeing his photos on a scandalous dating website, Breen was stunned.  He logged on and found it.

"Up comes pictures of myself, three pictures, that I posted on Facebook when I first signed up a while ago. This particular web site is something I didn't want to be associated with," said Breen.

Breen's pictures had been hijacked!  With hundreds of millions of photos being uploaded daily to popular social media sites, experts warn that even the savviest internet users are seeing their pictures and other personal media, copied and
shared without their consent.  Attorney Doug Isenberg likens it to digital shoplifting.

"Anything that you or I can create as long as it is an original work of authorship is protected under US Copyright Law.  It can include photographs, video, audio," Isenberg explained.

What's even scarier, reports are popping up around the world of stolen photos appearing in political attack ads, online scams, and even on foreign billboards, just to name a few.  

So what can you do if you discover you're a victim?   First, try contacting the site owner or content creator directly.  That's what Breen did.

"[I] said this is becoming more serious, please remove it, in capital letters, before I get, you know, someone involved, an attorney involved," explained Breen.

"You could send a cease and desist letter, citing violations of US Copyright Act and certainly in an extreme case you can file a complaint in court for copyright infringement," said Isenberg.

A simpler option would be to take preventative steps, like putting a visible watermark over things like photos and video.

"It's typically just a logo or a copyright image that's an overlay on top of your image," said Ben Bounketh with Digimarc, an Oregon-based company that enables businesses and governments worldwide to identify all forms of content, including audio, video and imagery.

But it's easy to crop the watermark out, or remove it through special software.  You can turn to a growing number of companies that offer other options, from software to give it a unique fingerprint, to digital watermarks that can't be seen by the naked eye.  Then they can't be tracked.

"We have a search service that's actually crawling the Internet.  The customer can then log in and view a report of where all of their images have been located," explained Bounketh. 

Channel 4 crime and safety expert Ken Jefferson says you should never post anything that's considered private, like pictures that reveal personal details.

"I know it's exciting when you get a new car or new home and you want to take pictures and show the world hey look what I've got but that's not the most prudent thing a person can do because stalkers and criminals will find you," said Jefferson.

In the meantime, Breen's threats to hire an attorney worked, but he has a warning for you the next time you post a picture.

"Think before you do it because you never know where the pictures will end up," he said.

Don't forget to change your privacy settings to be sure that only friends and family can see those photos.  Of course, they can still copy and save them to be used in other places, but at least you have cut back on the number of people who have access to them.

Read the United States Securities and Exchange Commission's statement on Facebook, Inc.