imagemagick = super.imagemagick.overrideAttrs(old: rec {
        version = "6.9.9-23";
        sha256 = "0cd6zcbcfvznf0i3q4xz1c4wm4cfplg4zc466lvlb1w8qbn25948";
        src = pkgs.fetchurl {
          url = "mirror://imagemagick/releases/ImageMagick-${version}.tar.xz";
          inherit sha256;
        };
      });