Yes, when you use the image tags to post photos on a website, it just places a link to wherever they're hosted (photobucket in this case). Most websites don't want to store thousands of photos, so they just link back to the original site. So, everyone who sees the photo on here, is actually connecting to your photobucket account to do so.
It MAY be possible that someone that has viewed your photos on here still has them in their computer's cookies folder. They may be able to look at the threads that had your photos in them and still see them, because they are temporarily stored on their computer. If that's the case, they could then save them, and send them to you. That may or may not be possible - I'm not really an expert.