The site code says that the image is in the / images / folder (for example, <a href="/images/img.png"></a>
)
the address of the image on the site looks like http://site.com/images/img.png using nginx to make the image link to the site at http://img.site.com/img.com or http: // img .site.com / images / img.com (the main thing is that the images are on a level 3 domain)