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View Full Version : Fetch/Retrieve 1st image in post and set it as featured image in wordpress



A Khan
01-06-2015, 05:56 AM
If you have a website have images in posts, but you had not set featured images for each post in past. And now you want to use featured image feature on wordpress. Then it will be very annoying for you to edit every post and set feature images for every single post. So here is a theme modification method for you, which help you to get the feature images from old posts.

Here is the code which scans the post, then pulls in the image set as 'featured'. If that doesn't exist, it returns the first image attached to the post. If there isn't one, it looks for any image in the post; if that's not there, it grabs a YouTube screenshot. Put this in your theme's functions.php file:


// Note that your theme must support post thumbnails for this function to work.
// If you are getting an error try adding add_theme_support('post-thumbnails'); to your functions. php file
function vp_get_thumb_url($text, $size){
global $post;
$imageurl="";

// 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];

// 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];
}

// 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];
}

// 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";
}

// Spit out the image path
return $imageurl;
}

To display this in your theme files, first insert the following:


<?php
if (function_exists('vp_get_thumb_url')) {
// Set the desired image size. Swap out 'thumbnail' for 'medium', 'large', or custom size
$thumb=vp_get_thumb_url($post->post_content, 'large-feature');
}
?>


and somewhere after that, to display the actual image (in category or single post file) in this case wrapped with a link to the post:

<?php if ($thumb!='') { ?>
<a href="<?php the_permalink() ?>" title="<?php the_title(); ?>" rel="bookmark"><img src="<?php echo $thumb; ?>" alt="<?php get_the_title(); ?>" /></a>
<?php } ?>
Search Google on the vp_get_thumb_url function name for other articles on how to implement this. Best of luck!

Joe Strummer
06-06-2016, 12:00 PM
Thank you for thread:)