For phpBB forumsoftware someone has programmed an extention that does exactly that; Copy all images in each thread/topic to the local server and update the imagelinks in the topics.
I was just thinking that. I could write a script that would automatically grab all the images and upload them locally. The problem why it won't work is for the same reason we can't see them, 3rd party access is blocked. If we can't see photobucket images on another site, then no script is going to be able to access them either. Unless you can spoof the originating IP making the http request, but it's not likely.
One possibility would be to make a web scraper for photobucket. If someone can link me a page on the forum with dead photobucket links, I'll give it a shot at pulling the images from PB.
