Hi there,
As I understand it - Sensitive Image Recognition (OCR) has an additional license requirement, however depending upon your subscription - it may be included in your suite of products. Please chat to your Account Rep to confirm
With versions 15.0, 15.1 and 15.1 MP1 - one limitation worth calling out is that images will not be detected in Microsoft Office products. This has now been resolved with version 15.5
OCR is configured by attaching an OCR Detection Engine (a separate OCR server running on Windows Server) to a Network Prevent or Discover server.
General sizing requirements are 1.25 OCR servers per Detection server (however this is dependant upon traffic throughput)