I've noticed that the SlimServer web interfaces seem to reload the images on
each refresh.  That is, they seem to go back to the HTTP server for the images
rather than load them from the browser's local cache.

This is bound to be causing unnecessary load on the server.  It's not a lot of
work, but it is a flurry of HTTP requests coming in at once.  And given that
some performance issues in serving streams seem to correlate with usage of the
web interfaces, I thought this might be worth a look.

S/W Config:
Server: SS6.0.0, WinXPsp2, server password is set
Client: Firefox 1.0.2, LiveHTTPHeaders, Win2000

I used the LiveHTTPHeaders extension for Firefox.  This allows me to see and
record the HTTP request/responses exchanges in realtime.  I loaded a playlist,
connected a player and let the stream run.  Waited for an automatic refresh of
the web UI.  The result was pretty standard, except for the image requests,
which looked like this:

http://myserver:9000/html/images/spacer.gif

GET /html/images/spacer.gif HTTP/1.1
Host: myserver:9000
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.6)
Gecko/20050317 Firefox/1.0.2
Accept: image/png,*/*;q=0.5
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer: http://myserver:9000/status_header.html?player=129.0.0.1&start=&refresh=1
Authorization: Basic obscured==
Pragma: no-cache
Cache-Control: no-cache

HTTP/1.x 200 OK
Cache-Control: public; max-age=15552000
Connection: keep-alive
Date: Wed, 06 Apr 2005 16:23:12 GMT
Content-Length: 43
Content-Type: image/gif
Expires: Mon, 03 Oct 2005 16:23:12 GMT
Last-Modified: Mon, 28 Mar 2005 18:52:50 GMT

The HTTP request portion is mostly OK.  What raises questions are the Pragma:
no-cache and Cache-Control: no-cache headers.  Pragma is mostly a legacy setting
that may affect caching proxies.  Cache-Control would seem to be directing the
browser to _never_ hold a copy of the image data in cache.

The HTTP response section indicates what looks to be a correct Last-Modified
date and a nice long time to it's Expires date.  This makes it look like the
intention is to cache these images.

If image caching is desired, there may be a non-trivial performance gain to be had.