Tnimage should compile in FreeBSD and NetBSD. It may be necessary to create symlinks for libtiff and libpng:
ln -s /usr/local/lib/libtiff* /usr/lib/ ln -s /usr/local/lib/libpng* /usr/lib/
If compilation fails with errors about operators `new' and `delete' make sure g++ is specified in the makefile, and not gcc. Tnimage requires a functional C++ compiler to build.