Since I signed up for a blogger account, I've been fighting with it to get it to display my header picture. Most people can just click on "Edit" in the header area and upload a picture. That wouldn't work for me. I was close enough to moving to another blogging provider that I went and created a Wordpress account, uploaded my header and posted a test post. If they hadn't killed the quality of my graphic, I'd be posting there right now. Unfortunately for Wordpress, and fortunately for Blogger (like either have anything to gain from my presence!) that ticked me off even more than not being able to use my image at all.
Being stubborn, I decided to spend whatever time it took to get it right. With a little suggestion from Beth, I figured out what I needed hack to get it to work: I had to change my header text to be one pixel tall black characters in a one pixel tall header container, expand the main container to 800px by 200px, and resize the body and sidebar containers accordingly.
Apparently I'm now learning to code in XML. whee! More changes are ahead, I'm sure.