gistfile1.rb

<% form_for setup_prototype(@prototype), :html => {:multipart => true} do |f| %>
  <%= f.error_messages %>

  <p>
    <%= f.label :title %><br />
    <%= f.text_field :title %>
  </p>
  <p>
    <%= image_tag @prototype.item_view.picture.url(:small) unless @prototype.new_record? %>
    <%= f.label :item_view %><br />
    <% f.fields_for :item_view do |item_view_form| %>
      <%= item_view_form.file_field :picture %>
    <% end %>
  </p>
  <p>
    <%= f.label :surface_views %>
    <% f.fields_for :surface_views do |surface_view_form| %>
      <div>
        <%= surface_view_form.label :description, 'Title' %>
        <%= surface_view_form.text_field :description, :size => 15 %>
        
        <%= surface_view_form.label :picture %>
        <%= surface_view_form.file_field :picture %>
        
        <% unless surface_view_form.object.new_record? %>
          <%= image_tag surface_view_form.object.picture.url(:small) %>
          <%= surface_view_form.label :_delete, 'Remove:' %>
          <%= surface_view_form.check_box :_delete %>
        <% end %>
      </div>
    <% end %>
  </p>
  <p>
    <%= f.submit @prototype.new_record? ? "Create" : "Update" %>
  </p>
<% end %>