how do i tell nginx to handle the file after fastcgi rewrites it?

I have a asp.net app and i am using nginx with fastcgi开发者_Python百科&mono. When i visit static.mysite.com/type/258/nicename.png i need nginx to grab the file from apppath/public/uploads/00/00/01/02 which is hex of 258. ATM i have asp.net rewriting the file however i am positive asp.net is still handling the file instead of nginx. I'm sure nginx would be faster and since i have the static subdomain i can skip asp.net if i have a way to tell nginx how to map the url to file

How do i get nginx to handle the file transfers?

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Check XSendFile.