You can do this with the setting in site.ini setting the convert executable. I dont have an eZ publish installation right here, so I don't remember the correct setting. Open your site.ini and search for "convert" and you will probably find the correct setting. Just change this setting to: convert -quality <value> -sharpen <radius>{x<sigma>} -rotate <degrees>{<}{>}
and you should be set. If you turn on debugging you will see the actual command that is being run (check to see if this is correct if it doesn't work as you want)
Jo Henrik Endrerud | System Developer @ Seeds Consulting | http://www.seeds.no