Issues using theme_image_style() on a multisite configuration

I do not find the trigger for Drupal creating the physical image. Somebody knows about it?

File: \modules\image\image.module
Lines: 83 - 90
Why: the multisite configuration is not supported by image core.

I can fix it setting an array with the multisite folder configuration but I want to set it as generic. How?

$sites = array('sites/default/files', 
                'sites/my_site_1/files', 
                'sites/my_site_2/files',
                'sites/my_site_3/files',);
  
  foreach ($sites as $site_path) {
    $items[$site_path . '/styles/%image_style'] = array(
      'title' => 'Generate image style',
      'page callback' => 'image_style_deliver',
      'page arguments' => array(count(explode('/', $site_path)) + 1),
      'access callback' => TRUE,
      'type' => MENU_CALLBACK,
    );
  }

Ideas?

Note: I want to mention that I am using the same DB instance for all sites and same Drupal core... Typical multisite configuration.

Adding items for each site into the image_menu solve the problem. I will create a patch to fix this.

$directory_path = file_stream_wrapper_get_instance_by_scheme('public')->getDirectoryPath();
  $items[$directory_path . '/styles/%image_style'] = array(
      'title' => 'Generate image style',
      'page callback' => 'image_style_deliver',
      'page arguments' => array(count(explode('/', $directory_path)) + 1),
      'access callback' => TRUE,
      'type' => MENU_CALLBACK,
    );
 
  //implementation of multisite image functionality
  foreach( file_scan_directory(DRUPAL_ROOT . '/sites', '//', array('recurse' => FALSE)) as $site_folders) {
    $folder_names_not_sites = array('all', 'default', 'sites', 'README');
    if( !in_array($site_folders->name, $folder_names_not_sites) ) {
      $site_folder_path = str_replace('default', $site_folders->name, $directory_path);
      $items[$site_folder_path . '/styles/%image_style'] = array(
        'title' => 'Generate image style',
        'page callback' => 'image_style_deliver',
        'page arguments' => array(count(explode('/', $site_folder_path)) + 1),
        'access callback' => TRUE,
        'type' => MENU_CALLBACK,
      );
    }
  }

I create the patch but not sure if I successfully uploaded to Drupal.

image-multisite-1965620-01.patch

Created patch !

Yes, I already have different sites under one Drupal core with one DB instance and Drupal itself support that. I created a custom module to handle the permission of content for the different sites, nothing fancy and it is the part that Drupal does not have as functionality. I wanted to implement the image problem and I think that should be part of Drupal core because I am not the only one trying to implement multisite using the same core and BD but they did not figure it out and this implementation can help to improve Drupal for multisite. Don't you think?

I already applied to my sites as part of a custom module but I believe this can be really useful for the Drupal community.