Over the last year or so I must have spent days trying to find the answer to this. I have a situation where I want to deliver a course that could be for a group of unlinked individuals, but could also be for people from a single organisation. I want to be able to use different copies of the course for each situation. For the unlinked people, I would have my branding all over it, and for the other I would make it clear that it is for their organisation.
My approach would be, if it is possible, to have a standard background to the course name area ("Pre-sessional B2+ ... in the screenshot) and the organisational branding as an image in the "General" section (blue image in the screenshot). As you can see, I can do the latter, but I can find no way to do the former.
Just installed Moodle version 3.10, but I have been trying with 3.8 and 3.9. I am using the Boost theme, updated today, but I am not wedded to it. It is not a live platform - I am running it on my PC at the moment.
Any pointers gratefully received.