WP function auto featured image

wp_auto_thumbnail_functions.php

<?php
 
/*
 * This function will get the first image in this order:
 *
 *    1) Featured image
 *    2) First image attached to post
 *    3) First image URL in the content of the post
 *    4) YouTube screenshot
 *    5) Default images for different categories [SET MANUALLY]
 *    6) Backup-default image if all else fails [SET MANUALLY]
 *
 * A big THANKS goes out to Michelle @ WordPress.StackExchange.com  
 * for her answer (http://bit.ly/O3UaLm) that made this possible!!!
 *
 */
 
//
// Activate post-thumbnails by adding this to theme's function.php file
//
add_theme_support('post-thumbnails');
 
 
//
// Add the following to the theme's function.php file
//
function vp_get_thumb_url($text, $size){
        global $post;
        $imageurl="";
 
// 1) FEATURED IMAGE
        // Check to see which image is set as "Featured Image"
        $featuredimg = get_post_thumbnail_id($post->ID);
        // Get source for featured image
        $img_src = wp_get_attachment_image_src($featuredimg, $size);
        // Set $imageurl to Featured Image
        $imageurl=$img_src[0];
 
// 2) 1ST ATTACHED IMAGE IMAGE
        // If there is no "Featured Image" set, move on and get the first image attached to the post
        if (!$imageurl) {
                // Extract the thumbnail from the first attached imaged
                $allimages =&get_children('post_type=attachment&post_mime_type=image&post_parent=' . $post->ID );
 
                foreach ($allimages as $img){
                        $img_src = wp_get_attachment_image_src($img->ID, $size);
                        break;
                }
                // Set $imageurl to first attached image
                $imageurl=$img_src[0];
        }
 
// 3) 1ST IMAGE URL IN POST
        // If there is no image attached to the post, look for anything that looks like an image and get that
        if (!$imageurl) {
                preg_match('/<\s*img [^\>]*src\s*=\s*[\""\']?([^\""\'>]*)/i' ,  $text, $matches);
                $imageurl=$matches[1];
        }
 
// 4) YOUTUBE SCREENSHOT
        // If there's no image attached or inserted in the post, look for a YouTube video
        if (!$imageurl){
                // look for traditional youtube.com url from address bar
                preg_match("/([a-zA-Z0-9\-\_]+\.|)youtube\.com\/watch(\?v\=|\/v\/)([a-zA-Z0-9\-\_]{11})([^<\s]*)/", $text, $matches2);
                $youtubeurl = $matches2[0];
                $videokey = $matches2[3];
        if (!$youtubeurl) {
                // look for youtu.be 'embed' url
                preg_match("/([a-zA-Z0-9\-\_]+\.|)youtu\.be\/([a-zA-Z0-9\-\_]{11})([^<\s]*)/", $text, $matches2);
                $youtubeurl = $matches2[0];
                $videokey = $matches2[2];
        }
        if ($youtubeurl)
                // Get the thumbnail YouTube automatically generates
                // '0' is the biggest version, use 1 2 or 3 for smaller versions
                $imageurl = "http://i.ytimg.com/vi/{$videokey}/0.jpg";
        }
// 4) YOUTUBE SCREENSHOT
        // If there's no YouTube video in the post, look for the default based on the category
        if (!$imageurl) {
                // Set default Image for different categories
                // [SET DIRECTORY MANUALLY!!]
                $dir = get_template_directory_uri() . '/images/'; // [SET MANUALLY!!!]
                // [DID YOU SET YOUR DIRECTORY?!]
 
                $get_cat = get_the_category();
                $cat = $get_cat[0]->
                slug;
                // [SET IMG EXT MANUALLY!!]
                $imageurl = $dir . $cat . '.jpg'; // [SET MANUALLY!!!]
                // [DID YOU SET YOUR IMG EXT?!]
 
                // Use this array if you have a few main categories that you want images for
                $array = array( 'cat_1', 'cat_2', 'cat_3',);
                if (!in_array($cat, $array))
                        // [SET BACKUP IMAGE MANUALLY!!!]
                        $imageurl = $dir . 'district.jpg'; // [SET MANUALLY!!!]
                        // [DID YOU SET YOUR BACKUP IMAGE?!]
        }
 
        // Spit out the image path
        return $imageurl;
}
 
 
//
// Add inside loop but before displaying image
//
if (function_exists('vp_get_thumb_url')) {
        // Set the desired image size.
        // Swap out 'thumbnail' for 'medium', 'large', or '[your-custom-size]'
        $thumb=vp_get_thumb_url($post->post_content, 'large-feature');
}
 
 
//
// Call the image inside the loop
//
?>
<a href="<?php get_permalink(); ?>" title="<?php the_title_attribute(); ?>" class="featured-image">
        <img src="<?php
                // Gets the image URL
                if ($thumb!='') echo $thumb;
        ?>" class="attachment-thumbnail wp-post-image" />
</a>
 
<?php
/*
 * A big THANKS goes out to Michelle @ WordPress.StackExchange.com
 * for her answer (http://bit.ly/O3UaLm) that made this possible!!!
 *
 */
?>