Nginx cache file by mime type

I use nginx as frontend, apache as backend. I need cache pictures, but by defa开发者_StackOverflow社区ult nginx is caching file by extentions. Apache takes pictures from db and send it without extentions. Can nginx cache files by mime type and how?

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You need something like this.

if ($upstream_http_content_type ~* "image/") {
    DEFINE_YOUR_CACHE_SETTINGS
}