The title overstates the point. Both these scripts in their latest versions are pretty darn good as are many of the other Lightbox type scripts out there (see end for two others or Google Lightbox for more, though not all are as good as those mentioned here, many including the original Lightbox mentioned in the title of this blog entry are).
Here's the real story -
Some time ago Dynamic Drive's Lightbox by Lokesh Dhakar was added to the Dynamic Drive official scripts.
Updated 07-08-2014 at 04:50 PM by jscheuer1
(add update for more recent jQuery versions)