Those are Google Adsense ads and it's a new-ish type of ad that combines content from the site with any applicable ads based on the content of the page being viewed.
In other words, if you are viewing a page on the site about Widgets then Google will try to display ads about Widgets to you and, based on space, some pages from the site that Google found related to Widgets. But if Google doesn't have any ads to display about Widgets then most of the slots, if not all, will be pages from the site that Google found related to Widgets.
For the most part I think that type of ad is the lesser of the evils of having to display ads; yeah, ads are still displayed but instead of having a chunk of screen display taken up entirely by nothing but ads this helps to get some notice to content on the site itself.
Oh, to answer the original point... the images displayed comes from the page linked and Luke found it, it was added on page #6 of that thread.