Related posts with images ( not featured thumbnail)

Question

I need to show the thumbnail size images (not featured thumbnail) from the posts on the "related posts", code below:

Thumbnail size (the images you insert into the posts from Media library) -vs- Featured thumbnail (is the new function "post-thumbnails" that you can attach an only image as featured image)

What I need:

[1] if the post has an only image, show it.

[2] if it has multi images, show the first.

[3] if non-images, show a static alternative.

Can anyone modify the code below, or have other good snippets to make that happen please? Many thanks!

<?php
$categories = get_the_category($post->ID);
if ($categories) {
    $category_ids = array();
    foreach($categories as $individual_category) $category_ids[] = $individual_category->term_id;
    $args=array(
        'category__in' => $category_ids,
        'post__not_in' => array($post->ID),
        'showposts'=> 5, // Number of related posts that will be shown.
        'caller_get_posts'=> 1
    );
    $my_query = new wp_query($args);
    if( $my_query->have_posts() ) {
        echo '<h3>Related Posts</h3>';
        echo '<ul>';
        while ($my_query->have_posts()) {
            $my_query->the_post();
        ?>
            <li><a href="<?php the_permalink() ?>"><?php the_title(); ?></a></li>
        <?php
        }
        echo '</ul>';
    }
}
wp_reset_query(); ?>

Answer 1

That is simple:

<?php
$categories = get_the_category($post->ID);
if ($categories) {
    $category_ids = array();
    foreach($categories as $individual_category) $category_ids[] = $individual_category->term_id;
   $args=array(
    'category__in' => $category_ids,
    'post__not_in' => array($post->ID),
    'showposts'=> 5, // Number of related posts that will be shown.
    'caller_get_posts'=> 1
);
$my_query = new wp_query($args);
if( $my_query->have_posts() ) {
    echo '<h3>Related Posts</h3>';
    echo '<ul>';
    while ($my_query->have_posts()) {
        $my_query->the_post();
    ?>
        <li><a href="<?php the_permalink() ?>"><?php the_title(); ?></a><?php echo catch_that_image() ?></li>
    <?php
    }
    echo '</ul>';
}
}
wp_reset_query(); ?>

In functions.php add this code:

function catch_that_image() {
  global $post, $posts;
  $first_img = '';
  ob_start();
  ob_end_clean();
  $output = preg_match_all('/<img.+src=[\'"]([^\'"]+)[\'"].*>/i', $post->post_content, $matches);
  $first_img = $matches [1] [0];

  if(empty($first_img)){ //Defines a default image
    $first_img = "/images/default.jpg";
  }
  return $first_img;
}

Of course, replace the default image path, and style the output to your needs.

Code taken from: http://www.wprecipes.com/how-to-get-the-first-image-from-the-post-and-display-it