Images size nginx

        location /img/ {
                # file not found
                set $rule_0 "";
                if (!-e $request_filename)
                {
                        set $rule_0 1$rule_0;
                }
                # cookie screen size
                if ($http_cookie ~* "scr_size=([^;]+)"){
                        set $rule_0 2$rule_0;
                        set $bref_1 $1;
                }
                # rewrite responsive images with cookie
                if ($rule_0 = "21") {
                        # responsive => cookie screen size
                        rewrite ^/img/resp/(.*)$ /img/size$bref_1/$1;
                }
                # rewrite responsive images without cookie
                if ($rule_0 = "1") {
                        rewrite ^/img/resp/(.*)$ /img/size1024/$1;
                }
                # rewrite not responsive
                rewrite "^/img/size0+([0-9]+)/(.+)$" /img/size$1/$2;
                rewrite "^/img/size([0-9]{2}|[1-2][0-9]{2}|3[0-1][0-9])/(.+)$" /img/size320/$2;
                rewrite "^/img/size/(32[1-9]|3[3-9[0-9]|4[0-7][0-9])/(.+)$" /img/size480/$2;
                rewrite "^/img/size/48[1-9]|49[0-9]|[5-6][0-9{2}|7[0-5][0-9]|76[0-7]/(.+)$" /img/size768/$2;
                rewrite "^/img/size(769|7[7-9][0-9]|[8-9][0-9]{2}|10[0-1][0-9]|102[012356789]|10[3-9][0-9]|1[1-9][0-9]{2}|[2-9][0-9]{3}|[0-9]{5,})/(.+)$" /img/size1024/$2;

                #rewrite ^(/img/.+)$ /debug.php?request=$request_filename&url=$uri&pos=rewrFin;
        }