I believe in the UK you can hold the copyright to the scan/photo of an artwork or image that is out of copyright. So the digital versions of these images are relatively new and the copywrite would be held by the person making the copy.
Are digitised copies of older images protected by copyright?
Simply creating a copy of an image won’t result in a new copyright in the new item. However, there is a degree
of uncertainty regarding whether copyright can exist in
digitised copies of older images for which copyright has
expired. Some people argue that a new copyright may
arise in such copies if specialist skills have been used
to optimise detail, and/or the original image has been
touched up to remove blemishes, stains or creases.
However, according to the Court of Justice of the
European Union which has effect in UK law, copyright
can only subsist in subject matter that is original in the
sense that it is the author’s own ‘intellectual creation’.
Given this criteria, it seems unlikely that what is merely
a retouched, digitised image of an older work can
be considered as ‘original’.
It's possible to create multiple derivative works of an out-of-copyright work, each of which will carry its own copyright. E.g. modern Sherlock Holmes stories. The question that matters is whether the scan involved enough creative work to qualify for copyright in its own right; as the sibling says, a simple scan won't, but a thorough restoration might.
