It usually offers a report feature directly under the main picture, but I have noticed that it's sometimes not there, nor the 'report user' option at the bottom of the profile page - just another POF oddity, I suppose. No that happens when you are not logged in. Log in again and magically it reappears.
POF has logged you out and you simply have not done anything yet to require you to be logged in and you have not noticed it yet.
OP if you are logged in properly the report pic button is right under their main photo always as long as you have been a member long enough to have that ability. I think you have to be a member for 30 days to report users or pics to keep the abuse down.