[PyQt] Missing icons (e.g. exit24.png) in PyQt5

[Virgil Stokes]

I recently (today) used pip to install the GPL version of PyQt5 on a 
Windows 10 platform far Python36 from: 
http://pyqt.sourceforge.net/Docs/PyQt5/installation.html. I started 
testing the installation with some coding examples at: 
http://zetcode.com/gui/pyqt5/introduction/. I found that the icons being 
used in some of their examples were not on my system. For example:

   web.png (in icon.py), exit.png (in simplemenu.py),  exit24.png (in 
toolbar.py), etc.

Why are these icons not found? What can I do to fix this?