<VirtualHost *:80>
        ServerAdmin admin@example.com
        ServerName example.com
        ServerAlias images.example.com
        Header set Access-Control-Allow-Origin "*"
        DocumentRoot /home/username/var/www/example.com/public_html
        ErrorLog /home/username/var/www/example.com/logs/error.log
        CustomLog /home/username/var/www/example.com/logs/access.log combined
</VirtualHost>

Forbidden
You don't have permission to access /test.txt on this server.

Apache/2.4.7 (Ubuntu) Server at images.example.com Port 80