Date   : Tue, 31 May 2005 12:07:14 +0000
From   : Jules Richardson <julesrichardsonuk@...>
Subject: Re: Picture and thumbnail sizes

On Mon, 2005-05-30 at 23:49 +0100, Jonathan Graham Harston wrote:
> > Message-ID: <1116968182.4586.71.camel@...>
>  
> Jules Richardson <julesrichardsonuk@...> wrote:
> > I'm trying to figure this out too. Somewhere around 150 x/y pixels for
> > thumbnails seems to work OK for galleries.
>  
> After browsing around a bit my question has changed to: does
> anybody know how to produce as good quality thumbnails as those on
> Drobe? Mine always come out really grainy. I did a test with the
> full-size picture of me on Drobe[1] and reduced it to the same
> size as Drobe's thumbnail, and it came out awful. So, I can get
> decent 100-ish pixel thumbnails if I do it properly.

Your drobe links give 404s :-(

I had a look at your attempt though; JPEG quality's down on what I
normally use (it's 85/100 in your file; I normally leave it on the
default here of 96/100)

The problem's more likely in whatever filter's used to scale your images
though. Lots of different algorithms exist for doing image scaling; have
a look at:

http://www.dylanbeattie.net/magick/filters/result.html

that's a comparison of the different ones that ImageMagick can use. In
particular, the 'Sinc' one at minimum blur looks very like the sorts of
results that you're getting (differences particularly noticeable with
the face images), compared to the other filters which do a lot better.

Maybe you should play around with whatever options the tools you're
using support, or switch to a different bit of software...

cheers

Jules