From: Tim Hunter <TimHunter@...>
Date: 2008-02-04T11:09:00+09:00
Subject: Re: Resizing pictures for file size

Marcin Raczkowski wrote:
>> There is no method in RMagick that takes an image and a file size in 
>> bytes and returns an image that, when saved to a file, produces a file 
>> close to or no larger than the specified size. The file size depends 
>> on the image format, the compression level, and the image itself.
> 
> There are tools that can estaminate size of file after compresion - but 
> they'll never give you exact size without actual compression.
> 
> So .. you take script, 20-30 simple images, take each one, start with 
> some quality - and incrementally decrase untill size fits, then you take 
> mean and min from qualities.
> 
> now you have 2 qualities - one that 50% of images should fit with size - 
> and second that almost all should fit.
> 
> that's assuming that your surce images have simillar resolutions.
> 
> greets
> 

Sounds like a plan. Maybe the OP will adopt it if he can't find a 
library that will do what he wants automatically.

-- 
RMagick: http://rmagick.rubyforge.org/
RMagick 2: http://rmagick.rubyforge.org/rmagick2.html