Fixed issue with duplicate thumbnails on ProductController#show

Fixes #2361

core/app/views/spree/products/_thumbnails.html.erb

@@ -1,19 +1,21 @@
-<!-- no need for thumnails unless there is more then one image -->
-<% if product.images.size > 1 || product.variant_images.size > 0 %>
+<%# no need for thumbnails unless there is more then one image %>
+<% if (@product.images + @product.variant_images).uniq.size > 1 %>
   <ul id="product-thumbnails" class="thumbnails inline" data-hook>
-    <% product.images.each do |i| %>
-      <li class="tmb-all" id="tmb-<%= i.id.to_s %>"><%= link_to image_tag(i.attachment.url(:mini)), i.attachment.url(:product) %></li>
+    <% @product.images.each do |i| %>
+      <li class='tmb-all' id='tmb-<%= i.id %>'>
+        <%= link_to(image_tag(i.attachment.url(:mini)), i.attachment.url(:product), :class => 'tmb-all', :id => "tmb-#{i.id}") %>
+      </li>
+    <% end %>
+
+    <% if @product.has_variants? %>
+      <% @variants.select(&:available?).each do |v| %>
+        <% v.images.each do |i| %>
+          <% next if @product.images.include?(i) %>
+          <li class='vtmb-<%= v.id %> vtmb' id='tmb-<%= i.id %>'>
+            <%= link_to(image_tag(i.attachment.url(:mini)), i.attachment.url(:product)) %>
+          </li>
+        <% end %>
+      <% end %>
     <% end %>
-    <% if @product.has_variants?
-      @variants.each do |v|
-        if v.available?
-          v.images.each do |i| %>
-            <li class="vtmb-<%= v.id.to_s %> vtmb" id="tmb-<%= i.id.to_s %>"><%= link_to image_tag(i.attachment.url(:mini)), i.attachment.url(:product) %></li>
-          <%
-          end
-        end
-      end
-    end
-    %>
   </ul>
 <% end %>

core/app/views/spree/products/show.html.erb

@@ -9,7 +9,7 @@
           <%= render :partial => 'image' %>
         </div>
         <div id="thumbnails" data-hook>
-          <%= render :partial => 'thumbnails', :locals => { :product => @product } %>
+          <%= render :partial => 'thumbnails' %>
         </div>
       </div>