Nginx cannot show many static images when using HTTP/2

One of my WordPress sites has a lot of static images (think at least 20 per page) and after I enable HTTP/2, the images in the lower part start to appear as broken (crossed out, like in images with dead links). Nothing wrong shows up in error.log file, but Chrome 53 says like this in the console:

Failed to load resource: net::ERR_SPDY_PROTOCOL_ERROR

I tried messing with client_max_body_size but that was no luck.

edit: this is my nginx.conf:

load_module /usr/local/libexec/nginx/ngx_mail_module.so;
load_module /usr/local/libexec/nginx/ngx_stream_module.so;
user  www;
worker_processes 4;
error_log  /var/log/nginx/error.log  info;

events {
        worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    sendfile        on;

    client_body_buffer_size 10K;
    client_header_buffer_size 1k;
    client_max_body_size 0;
    large_client_header_buffers 2 1k;
    client_body_timeout 12;
    send_timeout 10;
    #keepalive_timeout  0;
    keepalive_timeout  65;
    gzip off;
    charset UTF-8;

    server {
        listen       80;
        server_name manuth.life www.manuth.life;
        server_tokens off;
        return 301 https://$server_name$request_uri; #redirects to HTTPS
        root   /usr/local/www/nginx/manuth.life;
        index index.php index.html index.htm;
        access_log /var/log/nginx/manuth.life.access.log;
        error_log /var/log/nginx/manuth.life.error.log;

        error_page      500 502 503 504  /50x.html;

        # redirect server error pages to the static page /50x.html
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   /usr/local/www/nginx-dist;
        }
    }

    server {
        listen       443 ssl http2;
        server_name  manuth.life www.manuth.life;
        server_tokens off;
        root   /usr/local/www/nginx/manuth.life;
        index index.php index.html index.htm;
        access_log /var/log/nginx/manuth.life.access.log;
        error_log /var/log/nginx/manuth.life.error.log;

        # redirect server error pages to the static page /50x.html
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   /usr/local/www/nginx-dist;
        }

        # strict SSL settings
        ssl_certificate /usr/local/etc/letsencrypt/live/manuth.life/fullchain.pem;
        ssl_certificate_key /usr/local/etc/letsencrypt/live/manuth.life/privkey.pem;

        ssl_session_timeout 5m;
        ssl_protocols TLSv1.2;
        ssl_prefer_server_ciphers on;
        ssl_ciphers "EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH";
        ssl_ecdh_curve secp384r1; #
        ssl_session_cache builtin:1000 shared:SSL:10m;
        ssl_session_tickets off;
        ssl_stapling on;
        ssl_stapling_verify on;
        ssl_dhparam /usr/local/etc/ssl/dhparam.pem;
        resolver 8.8.8.8 8.8.4.4 valid=300s;
        resolver_timeout 10s;
        add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload";
        add_header X-Frame-Options DENY;
        add_header X-Content-Type-Options nosniff;

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

        location ~ \.php$ {
            try_files $uri =404;
            fastcgi_split_path_info ^(.+\.php)(/.+)$;
            fastcgi_pass unix:/var/run/php-fpm.sock;
            fastcgi_index index.php;
            fastcgi_param SCRIPT_FILENAME $request_filename;
            include fastcgi_params;
        }

    }

}