Many thanks for instant help. I stumbled because the import prompt says (approx.) "exported media files will be imported automatically". Since I have no way to export the old media I thought I was stuck.
I have completed export/import from adagiojournal.com to adagiojournal.wordpress.com. The source blog/media shows some 236 files, the new imported blog/media shows some 30 files.
The links that I have audited all still work because the source blog is still alive.
Example orphaned media:
Does this mean that all files in that /uploads/ path have been orphaned? Is there an automated process to recover these to the new blog?