RailsQ:What's the easiest way resize images on DH?

What’s the easiest way to resize an image on Dreamhost? Which image software? (i.e. ideally one that is already installed on the DH servers).

For example, which of the image tool options mentioned in this article would DH RoR developers recommend? (I’m a unix novice note) - http://clarkware.com/cgi/blosxom/2007/02/24#FileUploadFu


I see the ImageMagick is installed on shared servers, and the
ruby gem:

rmagick (1.14.1)
RMagick is an interface between the Ruby programming language and
the ImageMagick and GraphicsMagick image processing libraries.
… seems like this could be used to resize images.