Re: your mail

lilley (lilley@afs.mcc.ac.uk)
Mon, 3 Jul 1995 11:40:21 +0100 (BST)


From: lilley <lilley@afs.mcc.ac.uk>
Message-Id: <28733.9507031040@afs.mcc.ac.uk>
Subject: Re: your mail
To: brian@organic.com (Brian Behlendorf)
Date: Mon, 3 Jul 1995 11:40:21 +0100 (BST)
Cc: www-html@www10.w3.org
In-Reply-To: <Pine.3.89.9506271147.i10466-0100000@eat.organic.com> from "Brian Behlendorf" at Jun 27, 95 11:34:25 am

Brian Behlendorf said:

[about fine tuned content negotiation for images]

> In general, though, I think this kind of fine-tune negotiation should 
> occur as *close* to the client as possible - so that if three people 
> behind the Hensa proxy cache want different bitdepths of the same image, 
> hensa can download the canonical version of the image and downconvert 
> accordingly if it wants, rather than store three different versions.

The trade off between proxy filestore and image quality has been discussed 
before on this list. Those folks who see images as trivial decoration 
tend to prefer proxies playing fast and loose with image conversion, while
those who treat graphics as important content tend to prefer image
conversion done in a more controlled environment on the originating server.

To use an analogy, bar.html could be converted by a proxy to bar.txt, and 
then, later, bar.txt might be converted to bar.html again (add <pre> and 
</pre>) but the result would loose something in the process.

There is also the issue of which of a selection of image formats is the 
canonical one,  and how to expire foo.8bit..palette.png and foo.gif once 
foo.64bit.best.png changes. In other words, even if proxy conversion was ok, 
how do we express the dependencies?

 Content-type: image/png
 Makefile: http://foo/bar/Makefile

;-)

-- 
Chris Lilley, Technical Author
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