*Moved to Website Problems & Suggestions*
I'm not exactly sure when this happened, but some time ago Photobucket stopped allowing direct access to the full resolution images without them opening up on their website. As a result, all of the links that were created before the change no longer work as intended. I don't have a lot of time to run through all of the threads created with the old method of thumbnail/full-res linking, but have been trying to fix them as they pop up.
If you run across a problem with the links opening a very small thumbnail, you can see what the link states if you right click on it and select the 'copy link' option. Paste that into a new browser window and see what the link looks like. If it is linking to photobucket, but with the 'th_' prefix on the image filename, removing the 'th_' will load the full size image.
If the links aren't loading at all, I am not exactly sure what the problem might be. I will look over the P0440 thread and see what I can find.