They are not showing up for me, either.
Looking at the image URLs, it looks like they might be dynamically generated and time out/disappear after a time.
FreeAtlanta, it looks like you need to capture the images and host them yourself for them to be permanent.
Thanks for the validation on that.
Those sneaky bastages.
I thought it added more credibility if I linked to their lying data directly. I will rerun the graphs and post.