Header pictures removed

All of my head images have the been removed. For the most part I try to upload them directly instead of using the url option.

My main top banner has also been removed, when I try to upload another image of the same (even smaller) size it, it does not show up. I am using Google Chrome.

I'm not sure the cause of this, but it has happened to me a couple times. They have always returned on their own after a couple days.