Facebook is only displaying preview thumbnails that are 100px from my posts?

Question

I'm using Facebook and Digg Thumbnail generator and [FaceBook Share (New)], 2

As you can see if the image is 100px the thumbail is displayed when I press the share button:

But with an image with 300px of width:

The thumb preview doesn't appear:

front-page.php:

<?php
/**
 * Template Name: Front Page
 * @package WordPress
 * @subpackage Prominent
 * @since Prominent 1.0
 */
get_header(); ?>
<div id="tagline">
    <div class="container">
    </div><!-- .container -->
</div><!-- #tagline -->
<div id="content">
    <div class="container">
        <div id="mainbar">
            <?php while ( have_posts() ) : the_post(); ?>
                <div class="content-block-2">
                    <?php the_content(); ?>
                </div>
            <?php endwhile; ?>
            <?php /* Display navigation to next/previous pages when applicable */ ?>
            <?php if (  $wp_query->max_num_pages > 1 ) : ?>
                <div id="prev"><?php next_posts_link( __( '&larr; Older posts', 'twentyten' ) ); ?></div>
                <div id="next"><?php previous_posts_link( __( 'Newer posts &rarr;', 'twentyten' ) ); ?></div>
            <?php endif; ?>
        </div><!-- #mainbar -->
    </div><!-- .container -->
</div><!-- #content-bottom -->
<?php get_footer(); ?>

Any suggestion to solve this?

Answer 1

You can add Open Graph tags to your templates hint to Facebook for what images and text to use.

Answer 2

Finally figured out why. Facebook only allows images with 3:1 ratio.