<%= error_messages_for :photo %> <% form_for(:photo, :url => :photos, :html => { :multipart => true }) do |f| -%>

<%= f.label :image_file %>:
<%= f.file_field :photo %>

<%= f.label :category %> <%= f.select :category_id, @categories %>

<%= submit_tag 'Upload' %>

<% end -%>