One way to prevent it is to watermark your pics with your name.  I don't know how to do it, but I'm sure someone will be able to help you.  You can also copyright your pics so you would have some legal recourse the thief.

Thanks for sharing your experience and for the advice you have provided to all of us.  Sorry for your pic problems, but comfort yourself that you are not the first, and surely not the last.

LLAP,
Swim

Use a website like http://www.tineye.com/ when you are checking out a new girl's ad.  See if her pics appear on other places on the Web. That way sometimes you can tell she's faking it and using stolen pictures. Corey, very sorry you have to deal with this crap!

My info was taken and put on a very nasty website 2 weeks ago but that wasn't my first.  I think doing a google image search on a regular basis of your own images might help but sure would be a lot of work.  

For most men looking at an ad and those sexy pics their not going to do an image search.  

I had a friend touring in NY see my pics and ad there. She contacted me immediately because the phone number wasn't mine. I called that bit.... up screaming and she hung up on me. Backpage ad was down that quickly

Sorry this happened to you Corey

Kisses Haley

Make sure that your website designer or host has image split capabilities. This basically makes it extremely difficult for website visitors to steal your photos by splitting up your photos into 9 pieces with random file names. Another option that should be offered by any decent web designer is to off right click capabilities. This also makes it harder for pictures to be pulled from your site.  

Sorry you had to deal with this

An effective watermark needs to be hard to edit away, and sometimes that's tough to have that without being obtrusive, but I've seen a few ladies who have really nice watermarks (what I am using is not adequate - it's on my to-do list).

Most of the other methods are actually so easily circumvented one could argue whether it's even worth it.  They do perhaps stop some theft from the lowest denominator so it probably doesn't hurt to have them.  I won't mention the easy, almost foolproof method that does not require website expertise here because I suppose the fewer who know the better, but searching about this topic will give you an idea of how hard it is to truly protect anything on the web that can be publicly viewed.