CMS Prevent images in article preview?
 

Is it possible to prevent an image thumbnail from appearing in an article preview on the front page?

The reason I ask is because what i'm thinking of doing is having the 2 newest articles at the top of the page with a thumbnail and larger preview (i.e. more text), then have the older articles appear with less text and no thumbnail preview.

Then when I create a new article i'd change one of the others to no thumbnail and smaller preview text.

I know how to influence how much text is in the preview by using the preview break. But is there away of preventing a thumbnail from appearing for a particular article preview?