As of October 2006, I do not add a anymore the hi-res
pictures behind the medium-res pictures, as I run into the limits of the
diskspace I have with my provider.
As of December 2006 I have started adding hi-ress
pictures again since I moved to the site of the slide rule museum.
Last updated on December 23, 2009: now over a 165
different types (184 variations).