Although the NPC Book does not specifically state that pictures, etc. need to be hidden, it does say that Recruitment Counselors are to disassociate themselves from their chapter's membership recruitment activities. By keeping a Recruitment Counselor's photograph in a display or on a web site, this would directly contradict the disassociation clause.
Please contact your NPC Collegiate Panhellenic Advisor for additional clarification on this point. You can determine who your advisor is by going to the NPC site at
http://www.npcwomen.org.