I'm struggling because I'm using the "Sitewide Tags"-Plugin to grab all posts in a network to the main blog. Now I want to embed the post images to the main blog and the only function you're able to use for that is: the_post_thumbnail ();

But I'm using a grid layout for which I just need the url of the image (src). For that I cant't find the solution and would be very thankful for some help.

Best regards,


  • I am not sure how is that plugin influencing the process there. That function calls get_the_post_thumbnail() internally and looking at its source should give you the idea on how data is retrieved and formed.
    – Rarst
    Dec 19, 2013 at 16:22
  • Thanks! I tried that as well but without success...
    – Philipp
    Dec 19, 2013 at 16:46
  • get_the_post_thumbnail is correct. If you can't get that working, post the problematic code please.
    – s_ha_dum
    Dec 19, 2013 at 17:30
  • Thanks again. The problem is, that the plugin doesn't store the image in the post meta itself - As far as I understood. As you can read here (wpmututorials.com/plugins/post-thumbnails-for-sitewide-tags) it's also just possible to grab the "thumbnail" size. What is finde for me at the moment. As the_post_thumbnail(); is the only way (It is, I'm sure), I have to find a way to extract the src from it... :) Thank you very much in advance!
    – Philipp
    Dec 19, 2013 at 17:43

1 Answer 1


Get post thumbnail url with multisite

If you want to display materials on multisite function without switch_blog_id, then output the image material standard features wordpress fail. For this, I wrote this little function as a turnkey solution is nowhere found.

function multisite_thumb_url($pid, $bid){ //$pid - post id, $bid - blog id 
if(isset($pid) && $pid>0){
    if(isset($bid) && $bid>0){
        global $wpdb;
        $wpdb->set_blog_id( $bid );
        $post_thumbnail_id = $wpdb->get_var( "SELECT meta_value FROM {$wpdb->postmeta} WHERE meta_key = '_thumbnail_id' AND post_id = {$pid}" );
        $post_thumbnail_metadata = $post_thumbnail_id ? maybe_unserialize( $wpdb->get_var( "SELECT meta_value FROM {$wpdb->postmeta} WHERE meta_key = '_wp_attachment_metadata' AND post_id = {$post_thumbnail_id}" ) ) : NULL;
        if ( ! $post_thumbnail_metadata ){
            return false;
                $default_post_thumbnail_url = get_blog_option( $bid, 'siteurl' ).'/wp-content/uploads/'.$post_thumbnail_metadata[ 'file' ];
                $default_post_thumbnail_url = get_blog_option( $bid, 'siteurl' ).'/wp-content/uploads/sites/'.$bid.'/'.$post_thumbnail_metadata[ 'file' ];          
            return $default_post_thumbnail_url;
        $wpdb->set_blog_id( $curr_blog_id );
        return wp_get_attachment_url( get_post_thumbnail_id($pid) );
    return wp_get_attachment_url( get_post_thumbnail_id() );



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