Nginx rewrite rules help needed

Greetings!

Trying to test my new site on nginx and have one last rewrite rule to fix. Everything else is working
fine except for images, namely this:

RewriteRule ^file/([0-9]+)?/([0-9]+)x([0-9]+)/([^/\.]+) image.php?id=$1&width=$2&height=$3&cropratio=$4 [L]

So far I've tried the following rules:

rewrite ^/file/([0-9]+)?/([0-9]+)x([0-9]+)/([^/.]+) /image.php?id=$1&width=$2&height=$3&cropratio=$4 last;

and this one:

rewrite ^/file/([0-9]+)?/([0-9]+)x([0-9]+)/([^/\.]+) /image.php?id=$1&width=$2&height=$3&cropratio=$4 last;

but it still doesn't generate any images. I'm pulling my hair out and hope someone will know the trick. Maybe even a more elegant way to do this?

Thanks