If I understand correctly, you can’t save the background image from the VFB - what is the point then?
I did not know that - thank you! I did a search and all the posts says the background is only there for reference and can’t be saved.
There is another recent thread about this where I mentioned this checkbox is too much buried in the property panel for something so fundamental. I will look at how to make it more visible from the layer tree itself.
Related to that, I think the image should be saved to file by default instead of now being the opposite. Still giving the possibly to disable it but at least it would save some frustrating incomplete file output.