I finally procrastinated long enough for the technology to surpass my ignorance.
I added a picture to my header that I was working on last year. But my HTML knowledge (actually the CSS stuff) wasn't sufficient to make it work correctly. So this week when blogger finally made adding a picture to your header as simple as dragging and dropping… I was there!
I just had to resize, though I'm not satisfied with the placement, and there you go! As I learn more (by which I mean as Blogger becomes more powerful) I'll tweak it here and there.