Remote Upload

.htaccess

#Put this file in wp-content/uploads and modify remote domain.
#Copia este arhivo en wp-content/uploads and modifica el dominio remoto.

<IfModule mod_rewrite.c>
  RewriteEngine On
  RewriteBase /wp-content/uploads/
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule ^(.*) http://remotedomain.tld/wp-content/uploads/$1 [L,P]
</IfModule>

En el caso de local, tuve que crear un .htaccess así, en la raíz.

# BEGIN WordPress
RewriteEngine On
RewriteBase /

# custom rules for loading server images or any other uploaded media files
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{HTTP_HOST} ^dominio.local$
RewriteRule ^.*/uploads/(.*)$ http://dominioremoto.com/wp-content/uploads/$1 [L,R=301,NC]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
# END WordPress

Con nginx, es así:

server {
    server_name  _;
    return 302 $scheme://dominio.local$request_uri;
}

server {

    # Directives to send expires headers and turn off 404 error logging.
    location ~* \.(js|css|png|jpe?g|gif|ico)$ {
        expires 24h;
        log_not_found off;
        try_files $uri $uri/ @production;
    }

    location @production {
        resolver 8.8.8.8;
        proxy_pass https://dominioremoto.com/$uri;
    }

    server_name ~^(.*)\.dominio\.local$ dominio.local;
    root /app/public/;

    index index.php index.html index.htm;

}