Refactor nil image code, and add a built-in fix for missing nil images

templates/admin.html

@@ -21,6 +21,9 @@
             {% else %}
               {% include 'admin/logout.html' %}
               {% include 'admin/instructions.html' %}
+              {% if not config['USE_REMOTE_IMAGES'].value %}
+                {% include 'admin/image.html' %}
+              {% endif %}
               {% include 'admin/theme.html' %}
               {% include 'admin/retired.html' %}
               {% include 'admin/database.html' %}

templates/admin/image.html

@@ -0,0 +1,14 @@
+{% import 'macro/accordion.html' as accordion %}
+
+{{ accordion.header('Default images', 'image', 'admin', expanded=open_image, icon='image-line') }}
+<p>
+  If you do not see the following image, you either do not need them or you are coming from the original version of BrickTracker and or they have been moved.</code>.
+</p>
+<div class="d-flex justify-content-center border-bottom pb-2 mb-2">
+  <img class="table-img border mx-1" src="{{ nil_minifigure_url }}" alt="{{ nil_minifigure_name }}">
+  <img class="table-img border mx-1" src="{{ nil_part_url }}" alt="{{ nil_part_name }}">
+</div>
+<p>
+  <a href="{{ url_for('admin.update_image') }}" class="btn btn-primary" role="button"><i class="ri-download-line"></i> Update the images</a>
+</p>
+{{ accordion.footer() }}