Form sample code to do multiple photos upload inside photo gallery form

_form.html.erb

<%= form_for(@photo_gallery,:html => {multipart: true}) do |f| %>
  <% if @photo_gallery.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@photo_gallery.errors.count, "error") %> prohibited this photo_gallery from being saved:</h2>

      <ul>
      <% @photo_gallery.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :description %><br>
    <%= f.text_field :description %>
  </div>

  <div class="field">
    <%= f.label 'Photos' %><br>
    <% 10.times do |i| %>
       Photo <%= i + 1 %> &nbsp;
       <%= file_field_tag "photos[#{i}]", accept: 'image/png,image/jpeg' %> &nbsp;
       <%= @photo_gallery.photos[i].nil? ? '' : label_tag(@photo_gallery.photos[i].image_file_name,nil,id: "photo#{@photo_gallery.photos[i].id}") %> &nbsp;
       <br><br>
    <% end %>
  </div>

  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>