The thumbnail links you see on the forum are from images stored on ImageShack. ImageShack will generate the text you need to paste into your forum posts to create these thumbnail links. I don't believe Photobucket or FileFront will automatically do this. You could probably create the thumbnail links yourself (at least from Photobucket) by copying the links to the thumbnails on your image page and using that link and the direct link to the full size image with URL and IMG tags wrapped around them, but it would be a pain in the posterior.
Once again, I type (and think) too slowly:rotfl:I also think I misunderstood the question