Strange adwords in the cached version of my site

Just for a quick catchup session… Legal Beagles is a site that I recently registered to use as testing ground for SEO techniques and just about anything that is related to SEM.

After I completed the on-site SEO I decided to put some Google advertising on the site. Please see the bottom of my dummy attorneys website.

Everything was fine and then I decided to go have a look at the cached version of my site and was startled to find that the AdWords had been replaced by a banner advert (First time I have seen it on my site). Now I know Google has image ad formats but this particular one does not have the link at the bottom of the image that says “Feedback - Ads by Google”

Is it possible to have a picture on your blog that is actually a Google Ad but does not say so? If someone could provide any insight I would really appreciate it. Please post your thoughts in the comments.