This is the way.

I host my own images on my server using nginx to serve them from /var/www/images. You can see an example here: https://images.nunosempere.com/blog/2023/02/19/bayesian-adjustment-to-rethink-priorities-welfare-range-estimates/ignore-the-prior.png

The nginx configuration I'm using is

server {

        root /var/www/images;

        index index.html index.htm index.nginx-debian.html;

        server_name images.nunosempere.com;

        location / {
                # First attempt to serve request as file, then
                # as directory, then fall back to displaying a 404.
                try_files $uri $uri/ =404;
        }

    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/images.nunosempere.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/images.nunosempere.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

}
server {
    if ($host = images.nunosempere.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot

        listen 80;
        listen [::]:80;

        server_name images.nunosempere.com;
    return 404; # managed by Certbot

}