Header Image Not Showing Up

https://www.kbpictures.com/blog I haven’t been able to upload a header jpg or png from my computer in any theme. The image never appears on the crop page or on the site but it is in the media folder. Providing the URL address of the same jpg or png works so I don’t think there is anything wrong with image size, type etc. I have deleted, renamed, cleared cache, uploaded again. No success.
I’m using firefox 3.0.15

Thanks