Dynamic meta tags (getting images into meta)

[Prank]

Hi All,

Twitter does a pretty poor job of scraping content to boost the appearance of the Twitter Card in the tweet. Basically, if no og:image tag exists, Twitter shows a default thumbnail. Facebook at least crawls the page to grab an image.

Is there a method or property in $topic that will give me the URL's of any images? Or maybe in another variable somewhere? I could then just add the URL to the og:image meta myself and at least have good looking thumbs in Twitter. 

Thanks guys,

Christian