Close the media-upload thickbox right after upload is finished?

This was solved as simply as:

1. Hooking a custom .js script to the media-upload thickbox, so that it runs inside the iFrame:

   function admin_styles_scripts_media_upload() {
       wp_register_script('mediajs', get_template_directory_uri().'/js/button.js', array('jquery'), true);
       wp_enqueue_script('mediajs');
   
   }
   add_action('admin_print_scripts-media-upload-popup','admin_styles_scripts_media_upload');
   ?>
   

2. Use the script to replace the default Save button with a custom one, and call self.parent.tb_remove from that:

   jQuery(document).ready(function() {
   
       jQuery('<a href="#" id="back_to_admin" class="button">Voltar para Edição</a>').insertAfter('.ml-submit');   
       jQuery('.savebutton.ml-submit').detach();
       jQuery('a.toggle').live("remove");
   
       jQuery('#back_to_admin').live('click',function() {
   
           parent.uploadedImages();
           self.parent.tb_remove();
   
   });
   
   });