Reply To: Add Image Size to another ACF Field

• James

• October 3, 2016 at 11:54 am

Hi @neodjandre

You should be able to do it by using the acf/save_post hook like this:

function my_acf_save_post( $post_id ) {
    
    // get image id
    $image_id = get_field('fl_image', $post_id, false);
    
    // set the thumbnail field key
    $thumbnail_field_key = 'field_1234567890abc';
    
    // set the value of the thumbnail field
    update_field($thumbnail_field_key, $image_id, $post_id);
    
}

// run after ACF saves the $_POST['acf'] data
add_action('acf/save_post', 'my_acf_save_post', 20);

Where field_1234567890abc is the field key you want to update. After that, you can get the value like this:

$thumb_image = get_field(thumbnail_id);
$thumb_url = $thumb_image['sizes']['thumbnail'];

If you are using a URL custom field to store the URL, you should be able to do it like this:

function my_acf_save_post( $post_id ) {
    
    // get image id
    $image = get_field('fl_image', $post_id);
    
    // set the thumbnail URL field key
    $thumbnail_url_field_key = 'field_1234567890abc';
    
    // set the value of the thumbnail URL field
    update_field($thumbnail_url_field_key, $image['sizes']['thumbnail'], $post_id);
    
}

// run after ACF saves the $_POST['acf'] data
add_action('acf/save_post', 'my_acf_save_post', 20);

Then you can get the URL like this:

$thumb_image = get_field(thumbnail_id);

I hope this helps 🙂