I was playing around with a test template yesterday and noticed that Blogger users with the "new" style Blogger page element layouts can upload custom headers very much like any other image. (no need to have your photo or graphic hosted elsewhere) No fuss, no muss, just be sure you've got the size and cropping you want.
Go to customize your template, page elements, then your header and then edit. A "configure header" box will pop up with the customizing option.
I think it's a fairly new feature and don't recall seeing anything here at FBS on it. Of course, it could be real old news and something I just missed, but in case it is not, I wanted to share.
Faith from Blog Appetit (which still features its regular old rounders4 uncustom header)
PS: Blogger is doing that thing with showing every draft it auto-saved. If you've posted recently to FBS you may want to delete your unneeded drafts from the posts page.