Adding functions to Post Indexer

I’ve created a function to grab the post thumbnail using the Post Indexer plugin:

/**

* Network get post thumbnail

*/

function network_get_the_post_thumbnail( $blog_id = 0, $id = 0, $size = ‘post-thumbnail’, $attr = ”:wink: {

$post = &network_get_post( $blog_id, $id );

if(!empty($post)) {

switch_to_blog( $post->BLOG_ID );

$thumbnail = get_the_post_thumbnail( $post->ID, $size, $attr);

restore_current_blog();

return $thumbnail;

}

}

However, it’s not being recognized as a defined function. I added it to my functions.php equivalent, so I believe I just need to action to make it available to Post Indexer. If you could possibly provide that, that’d be great. Thanks!