Take a look which imagemagick packages are installed: $ aptitude search '~iimagemagick'
Probably there is a line beginning with i A imagemagick-6.q16 which shall replace imagemagick. Also see the dependencies of package imagemagick: $ dpkg -s imagemagick So before purging imagemagick you have to $ aptitude unmarkauto imagemagick-6.q16 Regards, jvp.