WordPress: Adicionando upload no campo Imagem na opção Links

// adiciciona o thickbox no campo imagem
add_action( 'admin_footer', 'wpmidia_link_image_scripts' );
function wpmidia_link_image_scripts(){
    global $current_screen;

    if( $current_screen->id == 'link' ):
    add_thickbox();
?>
<script type="text/javascript">
    jQuery(document).ready(function($) {

        var fileInput;
        var header_clicked = false;

        $('#link_image').click(function() {
            fileInput = $('#link_image');
            //formfield = jQuery('#upload_image').attr('name');
            //post_id = jQuery('#post_ID').val();
            tb_show('', 'media-upload.php?type=image&TB_iframe=true');
            header_clicked = true;
            return false;
        });

        window.original_send_to_editor = window.send_to_editor;
        window.send_to_editor = function(html){

            if (fileInput) { console.log(html);
                fileurl = $('img',html).attr('src');
                //fileurl = $(html).attr('src');
                console.log(fileurl);

                fileInput.val(fileurl);
                header_clicked = false;
                tb_remove();

            } else {
                window.original_send_to_editor(html);
            }
        };

    });
</script>
<?php
    endif;
}


/********************************************************
Shortcode
Como usar: dentro do post ou página, coloque:
[links]
Se quiser escolher qual categoria de links, coloque:
[links category=1] -- 1, 2 ou 3... será o ID da categoria de links =)
********************************************************/

function wpmidia_links_shortcode( $atts ){
    extract( shortcode_atts(
          array( 'category' => 2 ), $atts
        )
    );

    $bookmark = get_bookmarks(array('category' => $category));

    if( $bookmark ){
        echo '<div class="bookmark clearfix">';

        foreach( $bookmark as $link ){

            echo '<div class="link">';

            if( !empty($link->link_image) ){
                echo '  <div class="link_image"><img src="'.$link->link_image.'" width="150px" height="150px" /></div>';
            }

            echo '  <div class="link_desc"><p>'.$link->link_description.'</p><p>Link: <a href="'.$link->link_url.'" target="_blank">'.$link->link_name.'</a></p></div>';

            echo '</div>';
        }

        echo '</div>';

    } else {
        // mensagem se não houver links cadastrados...
        echo __('<p>Nenhum link cadastrado na base de dados</p>', 'labterra');
    }

}
add_shortcode( 'links', 'wpmidia_links_shortcode' );