libqtgui4: depende: libpng12-0 (> = 1.2.13-4) pero no está instalado
$ wget http://mirrors.kernel.org/ubuntu/pool/main/libp/libpng/libpng12-0_1.2.54-1ubuntu1_amd64.deb
$ sudo dpkg -i libpng12-0_1.2.54-1ubuntu1_amd64.deb
Important Ibis