How can I rewrite the marketpress code so shopping cart displays first image instead of featured ima

I'd like to rewrite the marketpress code so it calls for the first image within a post / product instead of the image set as "featured."

Suggestions welcome!

I'd like to do this because my theme displays the featured image in a poor, redundant way … revising the code is the only way I can effectively include the thumbnail within the shopping cart (screenshot).