$ sudo dpkg -i libpng12-0_1.2.54-1ubuntu1.1_amd64.deb
(Reading database ... 183096 files and directories currently installed.)
Preparing to unpack libpng12-0_1.2.54-1ubuntu1.1_amd64.deb ...
Unpacking libpng12-0:amd64 (1.2.54-1ubuntu1.1) ...
dpkg: error processing archive libpng12-0_1.2.54-1ubuntu1.1_amd64.deb (--install):
 unable to install new version of '/lib/x86_64-linux-gnu/libpng12.so.0': No such file or directory
Processing triggers for libc-bin (2.29-0ubuntu2) ...
Errors were encountered while processing:
 libpng12-0_1.2.54-1ubuntu1.1_amd64.deb

ryan@ryan-HP-Notebook:~$ runescape-launcher
/usr/share/games/runescape-launcher/runescape: error while loading shared libraries: libpng12.so.0: cannot open shared object file: No such file or directory