What do you mean with

I wrote this but I can't write a rule for global.php (wrapper for images?)

which part of .htaccess are you having trouble with?

here is the config I came up with for 6.10.2-stable
It is not production-ready and has no support for https/letsencrypt, but runs without errors and has some basic optimisation.

server
{
    listen 80;
    server_name www.yoursite.com;
    return 301 $scheme://yoursite.com$request_uri;
}

server
{
    listen 80;
    server_name yoursite.com;

    root /var/www/yoursite.com/;
    index index.php index.html;

#    access_log /var/logs/nginx/yoursite-access.log;
    error_log /var/logs/nginx/yoursite-error.log;

    etag on;
    client_max_body_size 128M;

    location ~* /htsrv/getfile.php/(.*)$
    {
		try_files $uri /htsrv/getfile.php?$args;
    }

    location ~* \.(png|jpg|ico|cur|gif|pdf|zip|jpeg|ttf|eot|woff)$
    {
		aio threads;
		gzip off;
		gzip_static off;
		add_header Cache-Control "max-age: 86640";
		access_log off;
		log_not_found off;
		etag on;
    }

    location ~* \.(js|map|html|css|json|htm|xml|txt)$
    {
		aio threads;
		add_header Cache-Control "max-age: 86640";
		access_log off;
		log_not_found off;
		etag on;
    }

    location = /favicon.ico { access_log off; log_not_found off; }
    location = /robots.txt { access_log off; log_not_found off; }


    location /api/
    {
		auth_basic          off;
		rewrite "^/api/v(?<version>[^/]+)/(?<parameters>(.+))$" /htsrv/rest.php?api_version=$version&api_request=$parameters last;
    }

    location /go/
    {
		rewrite "^/go/(?<key>(.+))$" /htsrv/track.php?key=$key last;
    }

    location ~ /\.svn|/\.git { deny all; internal; }
    location ~ /\. { deny all; internal; }

    if ( $http_user_agent ~* (nmap|nikto|wikto|sf|sqlmap|bsqlbf|w3af|acunetix|havij|appscan) ) { return 403; }

    location /
    {
       try_files $uri $uri/ /index.php?$args;
    }

    location ~ \.php(/|$)
    {
		gzip off;
		include fastcgi_params;
		
		fastcgi_param HTTP_PROXY '';
		fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name;
		fastcgi_param PATH_INFO $fastcgi_path_info;
		fastcgi_param DOCUMENT_ROOT $realpath_root;
		
		fastcgi_buffers 8 128k;
		fastcgi_buffer_size 256k;
		fastcgi_read_timeout 3000;
		fastcgi_keep_conn on;
		fastcgi_index index.php;
		
		fastcgi_pass 127.0.0.1:7777;
     }

}

I'll keep this topic updated and also add the rest of config (nginx server settings and php-fpm settings) after I do some load testing on a live server.

BTW, I have noticed that b2evo could be sped up by offloading a number of tasks to nginx instead of getting the job done by php.
For example, when there is a request for an image which is not cached yet, b2evo processes this image, than reads it and outputs to a client by itself, I mean this code

			if( ! file_exists( $af_thumb_path ) )
			{	// The thumbnail was not found...
				global $Settings;
				return '!Thumbnail not found in'.$Settings->get( 'evocache_foldername' ); // WARNING: exact wording match on return
			}

			if( ! is_readable( $af_thumb_path ) )
			{
				return '!Thumbnail read error! Check filesystem permissions.';
			}

			header('Content-Type: '.$thumb_mimetype );
			header('Content-Length: '.filesize( $af_thumb_path ) );
			header('Last-Modified: ' . date("r",$this->get_lastmod_ts()));

			// dh> if( $mtime && $mtime == $this->get_lastmod_ts() )
			// fp> I don't think mtime changes anything to the cacheability of the data
			//header_noexpire(); // Static image
			// attila> set expires on 30 days
			header('Expires: ' . date("r", $servertimenow + 2592000/* 60*60*24*30 = 30 days */ ));

			// Output the content of the file
			readfile( $af_thumb_path );
			return NULL;

But instead of using "readfile" which is far from optimal by many reasons (speed, scalability), with nginx we can just add one more header

header('X-Accel-Redirect: ' . $path);

and use this feature of nginx https://www.nginx.com/resources/wiki/start/topics/examples/xsendfile/
to send the file by nginx directly.
Moreover, it is a nice security feature because we can keep all the files/images out of the webroot folder, so they will not be accessible in a direct way.

Skin fallback functionality could be offloaded to nginx too, in my own cms I use nginx to make fallback lookups not only for php files but also for images, css files, js files - everything. So if I need to customize some skin, I have only to make a diff with altered images, styles and scripts and nginx does the rest.
I also use it to generate a compressed single file of all css styles (and for the most of js as well). Nginx tries to load a compacted version, and if it is not present or outdated - it makes a request to a php file which regenerates a new copy of compressed resources and saves it for nginx.

With all those little tricks I was able to decrease a cpu load by ten after switching from apache2..