The style is quite portrait-like, possibly reminiscent of the
pre-impressionist Dutch masters or of John Everett Millais. The
signature is C (or G, maybe) W Udorf 1847, with the year printed in a
German style with a large swash on the 1.
I've been through several sections of www.artrenewal.org and
www.allposters.com looking for a match, but nothing so far. A URL to an
image on the web of any size would be sufficient to identify it, and I'm
happy to try to run down any leads you can give. Thanks in advance for
your help.
-- Jon