He probably meant something like "*.jpg" which is common and works fine on Microsoft Windows and Apple OSX. And probably not the full Regex syntax as known from grep or Perl/PHP.
A wildcard search, then. Sure, that's more common (although sometimes hilariously broken), I can give you that.
I'd expect wildcard searches too, but only because Google is a search company. When I see a search box, I'm usually happy if it does a contains search instead of an exact match, that's how low my expectations have become.
