Lighttpd

I have mimetypes configured like this:

mimetype.assign           = ( ".png"  => "image/png",
                              ".PNG"  => "image/png",
                              ".gif"  => "image/gif",
                              ".GIF"  => "image/gif",
                              ".jpg"  => "image/jpeg",
                              ".JPG"  => "image/jpeg",
                              ".jpeg" => "image/jpeg",
                              ".JPEG" => "image/jpeg",
                              ".html" => "text/html",
                              ".txt"  => "text/plain",
                              ".css"  => "text/css" )

While gif-Images match this:

$ curl -I http://efops.serendipia.net/templates/default/img/xml.gif
[...]
Content-Type: image/gif, image/gif

Others seem to not match:

$ curl -I http://efops.serendipia.net/uploads/pics/ow.JPG
HTTP/1.1 200 OK
[...]
Content-Type: application/octet-stream