paginate in rails 2.3.3

Hi all,

i want to do paging in my project.
i am trying to using will_paginate but i can not do it.
i am follow following step

1. download will_paginate and put in vendor/plugin/
2. require 'will_paginate' in config/environment.rb
3. i want to use paging in image display so that in image controller

def index
    @images = Image.paginate :page => params[:page], :per_page => 5
  respond_to do |format|
    format.html # index.html.erb
    format.xml { render :xml => @images }
    end
  end

4. in Image model
        def self.per_page
            4
         end
5. in index.html.erb
          <%= will_paginate @image%>