Those are your Featured Image Thumbnails. If you don’t plan to use them, you could uncheck the Featured Image option in your Genesis Theme Settings.
If you do plan to use them on your Blog page but prefer to not have them show on your Single Posts/Pages then you can comment out or remove the code from your functions file –
Here’s the code that shows Featured Images on your Single Posts Pages (functions.php file) –
//* Add featured image above the entry content
add_action( 'genesis_entry_header', 'followme_featured_photo', 5 );
function followme_featured_photo() {
if ( is_attachment() || ! genesis_get_option( 'content_archive_thumbnail' ) )
return;
if ( is_singular() && $image = genesis_get_image( array( 'format' => 'url', 'size' => genesis_get_option( 'image_size' ) ) ) ) {
printf( '<div class="featured-image"><img src="%s" alt="%s" class="entry-image"/></div>', $image, the_title_attribute( 'echo=0' ) );
}
}