<div class="simple_form-field">
  <% if !@product.valid? && !@product.id || @product.photo_errors? || !@product.photo.file? %>
    <%= f.file_field(:photo) %>
    <% [:photo_file_size, :photo_file_name, :photo_content_type].each do |attr| %>
      <% if !@product.errors[attr].blank? %>
        <div class="field_error"><%= @product.errors[attr][0] %></div>
      <% end %>
    <% end %>
  <% else %>
    <div class="simple_form-field-photo">
      <p class="hidden"><%= f.file_field :photo, :id => 'product_image' %></p>
      <p id="product_image_text">
        <%= image_tag(@product.photo.url(:medium), :alt => @product.name) %><br>
      </p>
      <p><%= link_to_function("Change", "add_field('product_image', '', 'Cancel changes', this)") %></p>
    </div>
  <% end %>
</div>