Quantize/dither image using ImageMagick commands on image style actions Is there a way to use custom imagemagick commands on a image style action.
I'm trying to create a dither effect like the ones shown on the examples on the imagemagik site: http://www.imagemagick.org/Usage/quantize/#dither.

Here's another example: http://caca.zoy.org/study/out/lena5-2-1.png.

The command on the imagemagick website looks like this:

  convert colorwheel.png -dither Riemersma      -colors 16 dither_riemersma.gif


plus

  convert  logo.png  -remap pattern:gray50  mono_remap.gif
  convert -size 15x640 gradient: -rotate 90 \
                   -remap pattern:gray50     mono_remap_gradient.gif


but I don't know how or if it is possible to add this to an action.

Can someone shed some light on this? Is there an alternative method to accomplish this?
Imagecache actions has a 'custom' action which allows you to run your own actions. It may help you, though I used it years ago on a drupal 6 site with GD so can not say for certain if it will work for you.