I came here looking for how to add background images (to the whole page, not the content area). From your post, it looks like you can. I don't have that option. According to @mid, it looks like I might have additional options by enabling CSS.
However, I would like to mention, you can use custom HTML. Something as simple as adding a background-color (to the html), border, border-radius, color, bullets, numbers, sections, headings, etc., can all make your page look nice.