I successfully ran XnView MP on Ubuntu 16.04. Today I did "sudo apt-get dist-upgrade" and "sudo apt autoremove" and now XnView MP doesn't start anymore.
With "/opt/XnView/XnView" in the Terminal, I get the message:
"/opt/XnView/XnView: error while loading shared libraries: libQt5MultimediaWidgets.so.5: cannot open shared object file: No such file or directory"
PS: Thank you for XnView!
Have been using it for years now!