Sarah—
Thanks much. I’ve always thought of the two editors re posts rather than themes. I prefer Mac OS to Windows, Linux, or whatever; so I use the Mac desktop program MarsEdit as a blogging client. I use the online editor only for minor touch-ups on posts. The current and “classic” editors work equally as well for trivial stuff like that.
With themes, I’ve always just chosen from among the options provided, and the decisions have been easy: (1) Choose your layout (single column, righthand sidebar, perhaps footers). (2) Choose/create your header image and upload. (3) Choose/type your header info, if any. (4) Select the widgets you want, and arrange them in the order you want. (5) Setup done. Start writing.
But this time? I created the (persistent—top of every page) header image I wanted (conforming to the dimensions specified), uploaded it … and was presented with grotesquely distorted garbage.
I’ll attack it again tomorrow. But I admit it’s discouraging.