Help Needed RE: Proper Use of CMAKE_INSTALL_PREFIX in Installing ROOT

ROOT
3

Once you have build successfully the command

sudo cmake -DCMAKE_INSTALL_PREFIX=/usr/local/root -P cmake_install.cmake

should be sufficient. You do not need to reconfigure and rebuild just to change the installation prefix, which is by default /usr/local.
Concerning the missing library (libpng16.so.16) when run from the installation area we will need to debug it. Are you running in same node that you did the build? If the library in the build directory ( ~/root_build/lib ) ?