Unix commandline utilities for modifying images

[Alex Shaw]

>Does anyone know of any Unix command line utilities for
>converting/adjusting images?  The type of things I'm imagining are
>scaling, rotating and saving (probably to jpeg, if I could specify
>parameters such as quality, so much the better).  If anyone has
>examples showing usage that would be a help.  I'm running OSX 10.1.5
>The alternative is to use Applescript and a freely available
>application like Graphics Converter (which I know will work).

http://www.imagemagick.org

alex