Ok, I think the file might really be a .gif image...
I re-uploaded the image to the directory...
When I link directly to it, I can view it... As you can see below:

http://www.venturelandgames.com/them...mages/logo.gif

When I edit the "header.html" file to point it to logo.gif, it still doesn't show in the header. Am I editing the wrong file?