When viewing:
http://gitready.com/beginner/2009/01/21/pushing-and-pulling.html

The main diagram does not longer display. When navigating to the image url directly the site hosting it displays this message:

The owner of this website (osteele.com) does not allow hotlinking to 
that resource (/images/2008/git-transport.png).

The url in question is:
http://osteele.com/images/2008/git-transport.png

it is still available on here:
http://web.archive.org/web/20100104194951im_/http://osteele.com/images/2008/git-transport.png