Thank you for taking the time to report this bug and helping to make Ubuntu better. Unfortunately, we cannot work on this bug because your description didn't include enough information.ubuntu.com/DebuggingProcedures.
At a minimum, we need:
1. The specific steps or actions you took that caused you to encounter the problem.
2. The behaviour you expected.
3. The behaviour you actually encountered (in as much detail as possible).
Most importantly, please ensure that you include the release and flavour of Ubuntu that you are using.
Workaround:
sudo apt remove imagemagick-6.q16