Ars Technica has confirmed what a lot of us have suspected for a long time, that Facebook photos may never be truly "deleted" from Facebook's servers. That's the bad news.
The good news is that unless you're famous enough (or infamous) enough that people are actually linking to your Facebook photos from their e-mail or other places on the web, it is unlikely that anyone will see those "deleted" photos. It's also good news that as of this time, they can't be searched by your name. Finally, you may be relieved to know that this primarily applies to photos on Facebook - not comments or posts on Facebook.
So, how would the photos be found? By the image file (ending in .jpg) that is associated with that photo. You can find the link to the image file for just about any photo on the web by right-clicking on the photo, then selecting "properties," or "image properties," as your browser allows. Although it's a little more tedious, you can also find the link by clicking "view" at the top of your browser, then "source," then scrolling through to find the image file you're looking for.
With that image file address, it is possible to view images that may have been deleted from the site they were originally posted on - until the images are finally deleted from the server. Apparently, Facebook is not highly motivated to purge these old deleted files at this time (and why would they? Remember who their paying customers are).
Bottom line? This is a good time for a reminder not to post ANYTHING on the web you wouldn't want everyone in the world to see - including your family, friends, and potential customers or clients. Even if you have second thoughts and delete the content, you never know what that stuff could come back to haunt you.