diff --git a/core/event.php b/core/event.php
index 5ae1ad55..248bf6ae 100644
--- a/core/event.php
+++ b/core/event.php
@@ -154,7 +154,7 @@ class PageRequestEvent extends Event
     public function get_page_size(): int
     {
         global $config;
-        return $config->get_int('index_images');
+        return $config->get_int(IndexConfig::IMAGES);
     }
 }
 
diff --git a/core/imageboard/image.php b/core/imageboard/image.php
index 4277443c..c268266e 100644
--- a/core/imageboard/image.php
+++ b/core/imageboard/image.php
@@ -150,8 +150,8 @@ class Image
         $result = Image::get_accelerated_result($tag_conditions, $img_conditions, $start, $limit);
         if (!$result) {
             $querylet = Image::build_search_querylet($tag_conditions, $img_conditions);
-            $querylet->append(new Querylet(" ORDER BY ".(Image::$order_sql ?: "images.".$config->get_string("index_order"))));
-            if ($limit!=null) {
+            $querylet->append(new Querylet(" ORDER BY ".(Image::$order_sql ?: "images.".$config->get_string(IndexConfig::ORDER))));
+            if($limit!=null) {
                 $querylet->append(new Querylet(" LIMIT :limit ", ["limit" => $limit]));
                 $querylet->append(new Querylet(" OFFSET :offset ", ["offset"=>$start]));
             }
@@ -334,7 +334,7 @@ class Image
     public static function count_pages(array $tags=[]): float
     {
         global $config;
-        return ceil(Image::count_images($tags) / $config->get_int('index_images'));
+        return ceil(Image::count_images($tags) / $config->get_int(IndexConfig::IMAGES));
     }
 
     private static function terms_to_conditions(array $terms): array
diff --git a/ext/arrowkey_navigation/main.php b/ext/arrowkey_navigation/main.php
index 640d2b12..6464f592 100644
--- a/ext/arrowkey_navigation/main.php
+++ b/ext/arrowkey_navigation/main.php
@@ -52,7 +52,7 @@ class ArrowkeyNavigation extends Extension
         global $config, $database;
 
         // get the amount of images per page
-        $images_per_page = $config->get_int('index_images');
+        $images_per_page = $config->get_int(IndexConfig::IMAGES);
 
         // if there are no tags, use default
         if (is_null($event->get_arg(1))) {
diff --git a/ext/index/config.php b/ext/index/config.php
new file mode 100644
index 00000000..91329926
--- /dev/null
+++ b/ext/index/config.php
@@ -0,0 +1,11 @@
+<?php
+
+
+class IndexConfig
+{
+    public const IMAGES = "index_images";
+    public const SHOW_PAGE_SIZES = "index_show_page_sizes";
+    public const PAGE_SIZES = "index_page_sizes";
+    public const TIPS = "index_tips";
+    public const ORDER = "index_order";
+}
diff --git a/ext/index/events.php b/ext/index/events.php
new file mode 100644
index 00000000..35e58d35
--- /dev/null
+++ b/ext/index/events.php
@@ -0,0 +1,65 @@
+<?php
+
+/*
+ * SearchTermParseEvent:
+ * Signal that a search term needs parsing
+ */
+class SearchTermParseEvent extends Event
+{
+    /** @var null|string  */
+    public $term = null;
+    /** @var string[] */
+    public $context = [];
+    /** @var Querylet[] */
+    public $querylets = [];
+
+    public function __construct(string $term=null, array $context=[])
+    {
+        $this->term = $term;
+        $this->context = $context;
+    }
+
+    public function is_querylet_set(): bool
+    {
+        return (count($this->querylets) > 0);
+    }
+
+    public function get_querylets(): array
+    {
+        return $this->querylets;
+    }
+
+    public function add_querylet(Querylet $q)
+    {
+        $this->querylets[] = $q;
+    }
+}
+
+class SearchTermParseException extends SCoreException
+{
+}
+
+class PostListBuildingEvent extends Event
+{
+    /** @var array */
+    public $search_terms = [];
+
+    /** @var array */
+    public $parts = [];
+
+    /**
+     * #param string[] $search
+     */
+    public function __construct(array $search)
+    {
+        $this->search_terms = $search;
+    }
+
+    public function add_control(string $html, int $position=50)
+    {
+        while (isset($this->parts[$position])) {
+            $position++;
+        }
+        $this->parts[$position] = $html;
+    }
+}
diff --git a/ext/index/main.php b/ext/index/main.php
index 7a116df2..1e084f21 100644
--- a/ext/index/main.php
+++ b/ext/index/main.php
@@ -1,68 +1,7 @@
 <?php
 
-/*
- * SearchTermParseEvent:
- * Signal that a search term needs parsing
- */
-class SearchTermParseEvent extends Event
-{
-    /** @var null|string  */
-    public $term = null;
-    /** @var string[] */
-    public $context = [];
-    /** @var Querylet[] */
-    public $querylets = [];
-
-    public function __construct(string $term=null, array $context=[])
-    {
-        $this->term = $term;
-        $this->context = $context;
-    }
-
-    public function is_querylet_set(): bool
-    {
-        return (count($this->querylets) > 0);
-    }
-
-    public function get_querylets(): array
-    {
-        return $this->querylets;
-    }
-
-    public function add_querylet(Querylet $q)
-    {
-        $this->querylets[] = $q;
-    }
-}
-
-class SearchTermParseException extends SCoreException
-{
-}
-
-class PostListBuildingEvent extends Event
-{
-    /** @var array */
-    public $search_terms = [];
-
-    /** @var array */
-    public $parts = [];
-
-    /**
-     * #param string[] $search
-     */
-    public function __construct(array $search)
-    {
-        $this->search_terms = $search;
-    }
-
-    public function add_control(string $html, int $position=50)
-    {
-        while (isset($this->parts[$position])) {
-            $position++;
-        }
-        $this->parts[$position] = $html;
-    }
-}
+require_once "config.php";
+require_once "events.php";
 
 class Index extends Extension
 {
@@ -72,9 +11,9 @@ class Index extends Extension
     public function onInitExt(InitExtEvent $event)
     {
         global $config;
-        $config->set_default_int("index_images", 24);
-        $config->set_default_bool("index_tips", true);
-        $config->set_default_string("index_order", "id DESC");
+        $config->set_default_int(IndexConfig::IMAGES, 24);
+        $config->set_default_bool(IndexConfig::TIPS, true);
+        $config->set_default_string(IndexConfig::ORDER, "id DESC");
     }
 
     public function onPageRequest(PageRequestEvent $event)
@@ -167,7 +106,7 @@ class Index extends Extension
         $sb->position = 20;
 
         $sb->add_label("Show ");
-        $sb->add_int_option("index_images");
+        $sb->add_int_option(IndexConfig::IMAGES);
         $sb->add_label(" images on the post list");
 
         $event->panel->add_block($sb);
diff --git a/ext/numeric_score/main.php b/ext/numeric_score/main.php
index bff6701b..5e6d0f22 100644
--- a/ext/numeric_score/main.php
+++ b/ext/numeric_score/main.php
@@ -129,7 +129,7 @@ class NumericScore extends Extension
             $sql = "SELECT id FROM images
 			        WHERE EXTRACT(YEAR FROM posted) = :year
 					";
-            $args = ["limit" => $config->get_int("index_images"), "year" => $year];
+            $args = ["limit" => $config->get_int(IndexConfig::IMAGES), "year" => $year];
 
             if ($event->page_matches("popular_by_day")) {
                 $sql .=