[Clipart] reduce file size for png-files

[Alan Horkan]

On Sun, 19 Mar 2006, Open Clip Art Library Feedback Form wrote:

> Date: Sun, 19 Mar 2006 05:32:00 -0800 (PST)
> From: Open Clip Art Library Feedback Form <noreply at openclipart.org>
> Reply-To: clipart at lists.freedesktop.org
> To: clipart at lists.freedesktop.org
> Subject: [Clipart] reduce file size for png-files
>
>
> Name: Martin Bretschneider
> E-mail: emails-mmvi at bretschneidernet.de
>
>
> Hi,
>
> I tested some png-files of your animals category with optipng
> (http://www.cs.toronto.edu/~cosmin/pngtech/optipng/) that reduces the
> file size of png files up to 50%. I you try this you can save a lot of
> bandwidth on your server and on the side of the distributors and so
> on...

Sounds like they might be using 8-bit PNG or a greater level of zlib
compression which tends to produce significant space savings.  The reduced
colourspace would in most cases have more than enough colours to display
99% of our images, the greater zlib compression is a trade-off (bandwidth
versus user processing) I generally prefer not to make (in practice it can
sometimes make things feel slower but maybe it would be fine for small
thumbnails).  (I think some browsers+servers will even do zlib compression
of hte stream anyway but that is a whole other story.)

My point is if someone does decide to take the advice and compress things
further please consider the decision carefully (and maybe I should
consider that I am far more tired than I realised, hope you get the gist
of what I'm trying to say).

- Alan