htaccess - Redirect image and file request from the localhost to the production host if the file does not exist on the localhost. Needs to be placed in the root htaccess if you're using WordPress or another system that redirects all request to a index.php file.

htaccess-redirect-load-images-from-production

#place above all other rewrite rules if using a cms or program that redirects all request to index.php file (e.g. WordPress, Drupal, Laravel, etc...)
#if a file or directory does not exist on the local host, 302 redirect the request to the production host so the browser doesn't cache the file in case you replace the file locally
<IfModule mod_rewrite.c>
  RewriteEngine On
  #Redirect WordPress uploads
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteRule wp-content/uploads/(.*)$ http://www.example.com/wp-content/uploads/$1 [R=302,L,NC]
    
  #Redirect Nextgen Gallery uploads
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteRule wp-content/gallery/(.*)$ http://www.example.com/wp-content/gallery/$1 [R=302,L,NC]
</IfModule>