I am not sure if this is the correct location for a feature request, but here goes anyway:
In the authoring tool, it would be really fantastic if it were to be possible to set a background image per page /article/block/component.
this way it would be possible, without any css coding, to use an image as the background for the course, then another image for the background of the article, and even images for the background of text etc.
off course some extra controls are needed such as setting transparency etc etc.