我目前有2个图像位置,它们可能是格式(jpg,jpeg,png,gif)

i.domain.com/simage.jpg thumbnail
i.domain.com/image.jpg high quality
i.domain.com/o/image.jpg full resolution

有谁知道如何强制/ o /下载图像文件而不是在Web浏览器中渲染？

这是我的conf文件：http://pastebin.com/dP8kZMzx

#setup subdomain i.domain.com
server {
    server_name i.domain.com;
    access_log /var/log/Nginx/i..com.access.log;
    error_log /var/log/Nginx/i.domain.com.error.log;

    root /var/www/domain.com/test1/images;
    index index.PHP index.html index.htm;

    #error_page 403 = /notfound.jpg;
    #error_page 500 = /notfound.jpg;

    location / {            
        #change this to a 404 img file .jpg
        try_files $uri $uri/ /notfound.jpg;

        rewrite  "/s([A-Za-z0-9.]+)?" /small/$1 break;
        rewrite  "/o/([A-Za-z0-9.]+)?" /orig/$1 break;
        rewrite  "/([A-Za-z0-9.]+)?" /medium/$1 break;
    }

}