OK, I moved over to a windows machine and it looks like it can read all the images. I guess I will just have to finish my work on it. Thanks for the helping me narrow it down, it was giving me a headache.
I guess the problem was that they are just bad gifs?
Well, weird anyways. Some image viewers seem to open them, others don't, so it could be a problem with the image viewer or with the GIF. It's fair to say that they're "GIFs that tend to confuse image viewers", though. :-)