The file contains a JPEG image part, worth about 2kB to 7kB, as found by Save for Web.
It does not contain a color profile but plenty metadata XML, which seems to be responsible
for the size. Opening by Bridge as ACR doesn't show special information, with the exception of
an embedded camera profile. I don't know whether this is relevant or only a placeholder.
Best regards --Gernot Hoffmann
Thank you! It works.