GIMP can not do it

[Da Rock]

On Fri, 2008-03-14 at 18:34 -0500, Paul Johnson wrote:
> 2008/3/14 elk dolk <elkdolk at yahoo.com>:
> > Hi all,
> >
> > I have some 600x450 pixel photos and want to reduce their size  to 60K and
> > keep the aspect ratio, GIMP can't do it , anyone know of a Linux photo
> > manipulation SW for batch processing photos?
> >
> >
> 
> I do not know of a way to reduce with the goal of changing the file
> size.  I can tell you how to batch convert files to a particular
> resolution.  Save this batch program and run to change images to 600
> pixels wide jpeg quality 85.  It will take all files you list on the
> command line.
> 
> #!/bin/bash
> 
> for input in $@
> do
>   base=`echo $input | sed 's/\(.*\)\..*$/\1/'`
>   ##  echo "SUF" $SUF "base" $base
>   suffix="600.jpg"
>   /usr/bin/convert $input -resize 600x -quality 85 $base$suffix
> 
> done

As for Gimp, when you resize you need to ensure the little chain icon to
the right is actually complete by clicking on it. This will keep the
aspect ratio for you.

Also, unless I'm mistaken Gimp uses imagemagick to perform some tasks.
That may be a possibility for your needs in batch processing.