[Plugin: Get the Image] How do I display the "Featured Image"?

My current archive.php Loop uses get_the_image to display the first image from a post as a thumbnail next to the excerpt in the archive view.

I would like to have it display the image I’ve chosen as the “Featured Image” instead.

I’ve tried a number of things, including this:

<?php get_the_image(array('custom_key' => array('Feature', 'Feature Image'), 'default_size' => 'full')); ?>

and this:

<?php get_the_image( array( 'custom_key' => array( 'Feature' ), 'default_size' => 'full' ) ); ?>

and a whole bunch of other versions of similar code. However none of it seems to work.

Can someone tell me:

1. Is the “Featured Image”…you know, the one I choose on the bottom right hand corner of the Posts window when I’m creating the post, be targeted by get_the_image without me having to do any coding other than fixing this line in the Loop?

2. Exactly what code to use?

Also, I don’t know if it makes a difference or not, but I use NextGen Gallery and have chosen the “Featured Image” from a NextGen gallery instead of a direct upload (when I choose the “Featured Image” when creating the post, the option to choose it from the NextGen Gallery is available so I used that instead of wasting space with a separate upload).

Thank you very much for your help.