Thanks for your reply. Here is a complete .htaccess file:
<IfModule mod_rewrite.c>
SetEnv HTTP_MOD_REWRITE On
RewriteEngine on
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule . - [E=REWRITEBASE:/]
RewriteRule ^api/?(.*)$ %{ENV:REWRITEBASE}webservice/dispatcher.php?url=$1 [QSA,L]
# Images
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^([0-9])(\-[_a-zA-Z0-9-]*)?(-[0-9]+)?/.+\.jpg$ %{ENV:REWRITEBASE}img/p/$1/$1$2$3.jpg [L]
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^([0-9])([0-9])(\-[_a-zA-Z0-9-]*)?(-[0-9]+)?/.+\.jpg$ %{ENV:REWRITEBASE}img/p/$1/$2/$1$2$3$4.jpg [L]
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^([0-9])([0-9])([0-9])(\-[_a-zA-Z0-9-]*)?(-[0-9]+)?/.+\.jpg$ %{ENV:REWRITEBASE}img/p/$1/$2/$3/$1$2$3$4$5.jpg [L]
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^([0-9])([0-9])([0-9])([0-9])(\-[_a-zA-Z0-9-]*)?(-[0-9]+)?/.+\.jpg$ %{ENV:REWRITEBASE}img/p/$1/$2/$3/$4/$1$2$3$4$5$6.jpg [L]
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^([0-9])([0-9])([0-9])([0-9])([0-9])(\-[_a-zA-Z0-9-]*)?(-[0-9]+)?/.+\.jpg$ %{ENV:REWRITEBASE}img/p/$1/$2/$3/$4/$5/$1$2$3$4$5$6$7.jpg [L]
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])(\-[_a-zA-Z0-9-]*)?(-[0-9]+)?/.+\.jpg$ %{ENV:REWRITEBASE}img/p/$1/$2/$3/$4/$5/$6/$1$2$3$4$5$6$7$8.jpg [L]
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])(\-[_a-zA-Z0-9-]*)?(-[0-9]+)?/.+\.jpg$ %{ENV:REWRITEBASE}img/p/$1/$2/$3/$4/$5/$6/$7/$1$2$3$4$5$6$7$8$9.jpg [L]
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])(\-[_a-zA-Z0-9-]*)?(-[0-9]+)?/.+\.jpg$ %{ENV:REWRITEBASE}img/p/$1/$2/$3/$4/$5/$6/$7/$8/$1$2$3$4$5$6$7$8$9$10.jpg [L]
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^c/([0-9]+)(\-[\.*_a-zA-Z0-9-]*)(-[0-9]+)?/.+\.jpg$ %{ENV:REWRITEBASE}img/c/$1$2$3.jpg [L]
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^c/([a-zA-Z_-]+)(-[0-9]+)?/.+\.jpg$ %{ENV:REWRITEBASE}img/c/$1$2.jpg [L]
# AlphaImageLoader for IE and fancybox
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^images_ie/?([^/]+)\.(jpe?g|png|gif)$ js/jquery/plugins/fancybox/images/$1.$2 [L]
# Dispatcher
RewriteCond %{REQUEST_FILENAME} -s [OR]
RewriteCond %{REQUEST_FILENAME} -l [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^.*$ - [NC,L]
RewriteCond %{HTTP_HOST} ^example.com$
RewriteRule ^.*$ %{ENV:REWRITEBASE}index.php [NC,L]
</IfModule>
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/gif "access plus 1 month"
ExpiresByType image/jpeg "access plus 1 month"
ExpiresByType image/png "access plus 1 month"
ExpiresByType text/css "access plus 1 week"
ExpiresByType text/javascript "access plus 1 week"
ExpiresByType application/javascript "access plus 1 week"
ExpiresByType application/x-javascript "access plus 1 week"
ExpiresByType image/x-icon "access plus 1 year"
</IfModule>
FileETag INode MTime Size
<IfModule mod_deflate.c>
<IfModule mod_filter.c>
AddOutputFilterByType DEFLATE text/html text/css text/javascript application/javascript application/x-javascript
</IfModule>
</IfModule>
#If rewrite mod isn't enabled
ErrorDocument 404 /index.php?controller=404
Then I have to comment/delete mentioned directive:
SetEnv HTTP_MOD_REWRITE On
And yes, PS shows warning about non function mod_rewite module on webserver. Well, it is on... So, I'm going to contact my host tech support. Cheers.