Regarding ImageMagick - the most elegant way to deal with this would be as follows:
* Check if ImageMagick is available during installation, and list it as a warning if not - explain "You will have more image effects if ImageMagick is available"
* In the image editor itself, only show the sharpen button if you can detect that ImageMagick is available.
That way, anyone who goes to the effort of installing ImageMagick will be able to use sharpen, but we're still not overburdening people with lots of mandatory requirements. Best of both worlds!
Also, Mateusz - could you give us a confirmed, complete list of the actions that you would like so we can get Will to make icons?