NoMethodError in Photos#create

Showing app/views/photos/new.html.erb where line #22 raised:

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.empty?

Extracted source (around line #22):

19:     <% route = @thing.nil? ? @photo : [@thing, @photo] %>
20:     <% form_for route, :html => { :multipart => true } do |f| %>
21:       <div class="text"><%= f.label "photo", t(:"choose_file") %><%= f.file_field :file %></div>
22:       <% if @thing.class != Gallery && !@galleries.empty? %>
23:         <div class="text"><%= f.label "gallery_id" %><%= f.select "gallery_id", @galleries.map { |g| [g.title, g.id] }, :include_blank => true %>
24:       <% end %>
25:       <div class="button"><%= submit_tag t(:"upload") %> <%= t :"or" %> <%= link_to t(:"cancel"), :id => "cancel" %></div>

RAILS_ROOT: /biz/bangsr

app/views/photos/new.html.erb:22
app/views/photos/new.html.erb:20
app/controllers/photos_controller.rb:41:in `create'