I don't think the ports tree is quite that big, at least when it's compressed (presently ~220ish megs for FreeBSD 10 as a tgz), because ports only contain Makefiles and descriptive metadata.
It used to be the case, I think, that the extra disc images were for installing applications outside the base distributions and the likes as they themselves contained a snapshot of some of the binary archives for a given release. I don't know for sure, though, because I always used ports (which is better and obviously more up to date).
It used to be the case, I think, that the extra disc images were for installing applications outside the base distributions and the likes as they themselves contained a snapshot of some of the binary archives for a given release. I don't know for sure, though, because I always used ports (which is better and obviously more up to date).