I had a few minutes this morning to ponder whether messing with the XML within a workbook might be a quick 'n dirty work-around. Alas, I don't think this approach is viable. I compared the XML from a new, blank workbook with one that is blank except for
having a picture in the header. As you can see simply from the contents, quite a bit happens when a picture is inserted into the header. Page layout is affected. Print settings are affected. A thumbnail is built. A copy of the picture is embedded. It's not
as simple as just setting a reference to a picture.
This
screen shot compares the contents of a workbook having a picture in the header (left) and an empty workbook (right). The complexity of having a picture in the header is readily apparent.
There is irony in that having a picture in the header and footer was a Mac-only feature for many years. It was coveted by Windows users. Now they have it and we don't.