Recursive comparing of files

[Don Quixote de la Mancha]

I do understand that this isn't what you need, but I understand that
there are some tools available for Windows, that can go through
collections of JPEG photographs, and eliminate the duplicates based
not on the precise data, but on the appearance of the scene in the
image.

That is, if you had two visually-identical JPEGs of President Obama,
one encoded with JPEG high quality and the other with JPEG low
quality, the bits of the two files would be in no way correllated.
But these tools would be able to tell that they were both photos of
the same scene, and delete the low-quality version.

This sort of tool is very useful for people who like to... collect....
photographs...

I don't know of any tool like that for Linux though, or even for Mac
OS X.  I can't recall the names of any of the tools, just that they
were only available for Windows.

Don Quixote
-- 
Don Quixote de la Mancha
quixote at dulcineatech.com
http://www.dulcineatech.com

   Dulcinea Technologies Corporation: Software of Elegance and Beauty.