diff --git a/python/web/src/templates/index.html b/python/web/src/templates/index.html
index 4eb43528..580d46d5 100644
--- a/python/web/src/templates/index.html
+++ b/python/web/src/templates/index.html
@@ -156,8 +156,16 @@
         <li>{{ _("Select a valid SCSI ID and <a href=\"%(url)s\">LUN</a> to attach to. Unless you know what you're doing, always use LUN 0.", url="https://en.wikipedia.org/wiki/Logical_unit_number") }}
         </li>
         <li>{{ _("If RaSCSI was unable to detect the media type associated with the image, you get to choose the type from the dropdown.") }}</li>
-        <li>{{ _("Recognized image file types: %(valid_image_suffixes)s", valid_image_suffixes=valid_image_suffixes) }}</li>
-        <li>{{ _("Recognized archive file types: %(ARCHIVE_FILE_SUFFIXES)s", ARCHIVE_FILE_SUFFIXES=ARCHIVE_FILE_SUFFIXES) }}</li>
+        <li>
+            {{ _("Recognized image file types:") }}
+            {% set comma = joiner(", ") %}
+            {% for extension in valid_image_suffixes %}{{ comma() }}.{{ extension}}{% endfor %}
+        </li>
+        <li>
+            {{ _("Recognized archive file types:") }}
+            {% set comma = joiner(", ") %}
+            {% for extension in ARCHIVE_FILE_SUFFIXES %}{{ comma() }}.{{ extension}}{% endfor %}
+        </li>
     </ul>
 </details>
 
diff --git a/python/web/src/web.py b/python/web/src/web.py
index 288113fb..41db5e2a 100644
--- a/python/web/src/web.py
+++ b/python/web/src/web.py
@@ -149,7 +149,7 @@ def index():
         server_info["scmo"]
         )
 
-    valid_image_suffixes = "." + ", .".join(
+    valid_image_suffixes = (
         server_info["schd"] +
         server_info["scrm"] +
         server_info["scmo"] +
@@ -198,7 +198,7 @@ def index():
         username=username,
         auth_active=auth_active(AUTH_GROUP)["status"],
         PROPERTIES_SUFFIX=PROPERTIES_SUFFIX,
-        ARCHIVE_FILE_SUFFIXES="." + ", .".join(ARCHIVE_FILE_SUFFIXES),
+        ARCHIVE_FILE_SUFFIXES=ARCHIVE_FILE_SUFFIXES,
         REMOVABLE_DEVICE_TYPES=ractl_cmd.get_removable_device_types(),
         DISK_DEVICE_TYPES=ractl_cmd.get_disk_device_types(),
         PERIPHERAL_DEVICE_TYPES=ractl_cmd.get_peripheral_device_types(),