That returns an image inline when viewing in a browser.
LWP's get() just returns the source of the file without client-side processing. Can I pipe it to some virtual machine and get back the output?
you could try playing with the google adsense preview tool. If I recall correctly (been a few years since I wrote a script using it), there is an API that will return ads for any page or keyword in test-mode. use the preview tool, find the api (or find it by searching the web, it's been done before, look for adsense sandbox and similar keywords) and see wether it returns images as well (I know for sure it gives you those text-ads, image-ads hadn't been around when I played with it).
btw, you might want to remove the google-clientid etc from your post, it's not wise if it's yours and it's not nice if it's not yours.