I don't have a Pi with Ubuntu MATE and I'm not sure if these packages are preinstalled but you can try to remove them and see what happens:
sudo apt-get remove --purge libjpeg8 libjpeg-turbo8 smplayer-skins
Of course, if the list of removed packages seem odd (like trying to remove half of your system), don't validate... In doubt, paste the list of the packages here.
If nothing too bad happens, you's probably need to remove orphaned dependancies:
sudo apt-get autoremove --purge
You can then try to reinstall either libjpeg8 or libjpeg-turbo8 (not both, as they seem to be the ones that have common files) and then smplayer-skins.