libpng
https://github.com/glennrp/libpng
zlib
https://github.com/madler/zlib/releases
https://github.com/madler/zlib/releases/tag/v1.2.8
打开,libpngprojectsvstudio
zlib-1.2.8 需要放在和libpng源码的同一级目录、(详见 libpngprojectsvstudiozlib.props)