I feel such a schoolboy posting this - this should be so simple.
I can drag a jpg (or png) background to the top track in my project - but it simply doesn't show up in the video preview. Everything else shows up in the video preview, just not the static jpg background file (even when on top) - it is simply invisible. I have tried resetting all my settings to default, importing the file in different ways, deleting all other files in the project, and many other things over the last few hours, and - even - restarting my laptop - but I remain beaten. Badly beaten.
The (obvious to everyone else) solution would be very welcome.
DE