All,

This has been an interesting discussion and frankly it is not uncommon in my
experience for these kinds of questions to arise. Not sure I have anything
to add in terms of answers, but see my response below to one part of Peter
Keane's recent message.

Looked at another way: a thumbnail is just a bit of "visual" metadata,
> and you cannot copyright metadata.


Well, it's been tried before.  In the mid-80s there was a big hullabaloo
over what was seen or interpreted as OCLC copyrighting all MARC records in
its WorldCat database.  See the following informative website that goes into
the context and history of the incident:

Guidelines for the Use and Transfer of OCLC-Derived Records [OCLC]
http://www.oclc.org/support/documentation/worldcat/records/guidelines/

Steve