I don't know why.. but I'll try to fix them soon.
edit--the help forum for forumotion happens to have a thread on this already. it hasn't been marked "solved" yet, but someone is saying that they had to re-upload all the images. I'm gonna look around some more and see if there's anything else we can do, because I surely hope that we don't have to re-upload everything, in fact, I might not still have the files I've uploaded. HOPEFULLY, there'll be something else we can do instead of re-uploading everything.