Display a Single Image in Excerpt

I am using WordPress as an internal tool to document our interface design patterns. On the search results page I want to display the title of the post along with a single image related to the post. Using the functions.php file I have added this code:

<?php
function improved_trim_excerpt( $text ) {
	if ( '' == $text ) {
		$permalink = get_permalink();	// my addition
		$text = get_the_content( '' );
		$text = strip_shortcodes( $text );
		$text = apply_filters( 'the_content', $text );
		$text = preg_replace( '@<script[^>]*?> . *?</script>@si', '', $text );
		$text = str_replace( ']]>', ']]>', $text );
		$text = strip_tags( $text, '<b><em><i><p><strong><sub><sup><h1><h2><h3><img>' ); // allowed tags (change as needed)
		$excerpt_length = apply_filters( 'excerpt_length', 10 );

		$words = explode( ' ', $text, $excerpt_length + 1 );
		if ( count( $words ) > $excerpt_length ) {
			array_pop( $words );
			$text = implode( ' ', $words );
			$text = $text . $excerpt_more;
			$text = force_balance_tags( $text );	// my addition
		}
	}
	return $text;
}
remove_filter( 'get_the_excerpt', 'wp_trim_excerpt' );
add_filter( 'get_the_excerpt', 'improved_trim_excerpt' );
?>

This allows the images to show up but it also shows other text. I only want images to appear. Thoughts?

Thanks in advance,
Grant Novey