When software makes it hard to gain access to something, some people would call this a "security feature". But to make something truly secure, the software has to be written in such a way that it is designed to make it hard to get at the something.
The producer of "zoomify" explicitly says that their software should not be considered a security feature. That may make sense on several levels
- the software was not designed with security in mind
- the producer does not want to be liable for any exploits of the software