It can work to your advantage to have a next link on your pictures and also include a link elsewhere that you want to send traffic - to a sponsor or page of links, something like that. By the time the surfer gets 10 pics in they may not want to hit the back button ten times and would more than likey click through to the sponsor or other site you have a link to and if they are horny enough, possibly nabbing you a sale! It's a technique I like to use when building an AEN tour, enticing the surfer to click the next links and finally landing on the join page.