Full URL for Images

I can’t seem to get the URL for the Full Size attached image. I have tried every single line – copied and pasted in the references but nothing.

I can output the normal thumbnail image perfectly OK, but as soon as I paste the array data I get no return.

The code I’m using:

$image_url = apply_filters( 'taxonomy-images-queried-term-image-url', '', array('image_size' => 'medium') );

I then use it to attach a image to my meta data like this:

<meta property="og:image" content="<?php print $image_url ?>" />

https://www.ads-software.com/plugins/taxonomy-images/