ulfben

/*refactored version of http://pastebin.com/f5cdfcd4c */

/*returns one image per (published & public) post.
use params to control the number of posts, the categories, the sort order and image size.
    @returns array(array('post_url', 'post_title','post_id','img_src'), [...])*/
function ulfben_get_post_images($number_of_posts = 5,
                        $category_filter         = '66', //comma delimited list of category IDs
                        $order_by            = 'RAND()', //{$wpdb->posts}.post_date DESC or what have you.
            $size = 'thumbnail'){//'thumbnail', 'medium', 'large' or 'full' or an array of width and height, e.g. array(32,32)
    global $wpdb;
    $limit = (is_int($number_of_posts) && $number_of_posts > 0) ? $number_of_posts : 1; //select 1 if the parameter seems stupid.
    $query="SELECT {$wpdb->posts}.post_parent, {$wpdb->posts}.ID
            FROM {$wpdb->posts}
            INNER JOIN {$wpdb->term_relationships} ON ({$wpdb->posts}.post_parent = {$wpdb->term_relationships}.object_id)
            INNER JOIN {$wpdb->term_taxonomy} ON ({$wpdb->term_relationships}.term_taxonomy_id = {$wpdb->term_taxonomy}.term_taxonomy_id)
            WHERE {$wpdb->posts}.post_type = 'attachment'
            AND {$wpdb->term_taxonomy}.taxonomy = 'category' AND {$wpdb->term_taxonomy}.term_id IN ('{$wpdb->escape($category_filter)}')
            AND {$wpdb->posts}.post_password = ''
            AND {$wpdb->posts}.post_mime_type IN ('image/jpeg', 'image/gif', 'image/png')
            GROUP BY {$wpdb->posts}.post_parent
            ORDER BY {$order_by}
            LIMIT {$limit};";
    $results = $wpdb->get_results($query);
    $selection = array();
    foreach($results as $result){
        $parent_post_id = $result->post_parent;
        $image_id = $result->ID;
        $imgurl = wp_get_attachment_image_src($image_id, $size);
        if($imgurl === false){continue;} //the image doesn't exist in the requested size!
        $imgurl = $imgurl[0];
        $post_url = get_permalink( $parent_post_id );
        $post_title = $wpdb->get_var("SELECT {$wpdb->posts}.post_title
                        FROM {$wpdb->posts}
                        WHERE {$wpdb->posts}.ID = {$parent_post_id}
                        LIMIT 1;"
                    );
        $selection[] = array('post_url'=>$post_url, 'post_title' => wp_specialchars($post_title),'post_id'=>$parent_post_id, 'img_src'=>$imgurl);
    }
    return $selection;
}

function ulfben_print_post_images($number_of_posts = 5, //number of posts
                     $image_attributes         = '',
                                 $category_filter          = '66', //comma delimited list of category IDs
                                 $order_by             = 'RAND()', //{$wpdb->posts}.post_date DESC or what have you.
                     $size = 'thumbnail'){//'thumbnail', 'medium', 'large' or 'full' or an array of width and height, e.g. array(32,32)
    $images = ulfben_get_post_images($number_of_posts, $category_filter, $order_by, $size);
    foreach($images as $image){
        echo "<a href='{$image['post_url']}' title='{$image['post_title']}'><img src='{$image['img_src']}' alt='{$image['post_title']}' {$image_attributes}/></a>";
    }
}