diff --git a/ext/relatationships/main.php b/ext/relatationships/main.php
index 5304e3a5..eaae08b9 100644
--- a/ext/relatationships/main.php
+++ b/ext/relatationships/main.php
@@ -1,13 +1,29 @@
 <?php
 /**
  * Name: Post Relationships
- * Author: Angus Johnston <admin@codeanimu.net>
+ * Author: Angus Johnston <admin@codeanimu.net, Matthew Barbour <matthew@darkholme.net>
  * License: GPLv2
  * Description: Allow posts to have relationships (parent/child).
  */
 
+class ImageRelationshipSetEvent extends Event
+{
+    public $child_id;
+    public $parent_id;
+
+
+    public function  __construct(int $child_id, int $parent_id)
+    {
+        $this->child_id = $child_id;
+        $this->parent_id = $parent_id;
+    }
+}
+
+
 class Relationships extends Extension
 {
+    public const NAME = "Relationships";
+
     protected $db_support = [DatabaseDriver::MYSQL, DatabaseDriver::PGSQL];
 
     public function onInitExt(InitExtEvent $event)
@@ -35,7 +51,7 @@ class Relationships extends Extension
     {
         if (isset($_POST['tag_edit__tags']) ? !preg_match('/parent[=|:]/', $_POST["tag_edit__tags"]) : true) { //Ignore tag_edit__parent if tags contain parent metatag
             if (isset($_POST["tag_edit__parent"]) ? ctype_digit($_POST["tag_edit__parent"]) : false) {
-                $this->set_parent($event->image->id, (int) $_POST["tag_edit__parent"]);
+                send_event(new ImageRelationshipSetEvent($event->image->id,(int) $_POST["tag_edit__parent"]));
             } else {
                 $this->remove_parent($event->image->id);
             }
@@ -75,12 +91,12 @@ class Relationships extends Extension
             if ($parentID == "none" || $parentID == "0") {
                 $this->remove_parent($event->id);
             } else {
-                $this->set_parent($event->id, $parentID);
+                send_event(new ImageRelationshipSetEvent($event->id, $parentID));
             }
         } elseif (preg_match("/^child[=|:]([0-9]+)$/", $event->term, $matches) && $event->parse) {
             $childID = $matches[1];
 
-            $this->set_child($event->id, $childID);
+            send_event(new ImageRelationshipSetEvent($childID, $event->id));
         }
 
         if (!empty($matches)) {
@@ -102,29 +118,45 @@ class Relationships extends Extension
         }
 
         if ($event->image->parent_id !== null) {
-            $database->execute("UPDATE images SET has_children = (SELECT * FROM (SELECT CASE WHEN (COUNT(*) - 1) > 0 THEN 1 ELSE 0 END FROM images WHERE parent_id = :pid) AS sub)
-								WHERE id = :pid", ["pid"=>$event->image->parent_id]);
+            $this->set_has_children($event->image->parent_id);
         }
     }
 
-    private function set_parent(int $imageID, int $parentID)
+    public function onImageRelationshipSet(ImageRelationshipSetEvent $event)
     {
         global $database;
 
-        if ($database->get_row("SELECT 1 FROM images WHERE id = :pid", ["pid"=>$parentID])) {
-            $database->execute("UPDATE images SET parent_id = :pid WHERE id = :iid", ["pid"=>$parentID, "iid"=>$imageID]);
-            $database->execute("UPDATE images SET has_children = TRUE WHERE id = :pid", ["pid"=>$parentID]);
+        $old_parent = $database->get_one("SELECT parent_id FROM images WHERE id = :cid", ["cid"=>$event->child_id]);
+
+        if($old_parent!=$event->parent_id) {
+            if ($database->get_row("SELECT 1 FROM images WHERE id = :pid", ["pid" => $event->parent_id])) {
+
+                $result = $database->execute("UPDATE images SET parent_id = :pid WHERE id = :cid", ["pid" => $event->parent_id, "cid" => $event->child_id]);
+
+                if ($result->rowCount() > 0) {
+                    $database->execute("UPDATE images SET has_children = TRUE WHERE id = :pid", ["pid" => $event->parent_id]);
+
+                    if($old_parent!=null) {
+                        $this->set_has_children($old_parent);
+                    }
+                }
+            }
         }
     }
 
-    private function set_child(int $parentID, int $childID)
+
+    public static function get_children(Image $image, int $omit = null): array
     {
         global $database;
-
-        if ($database->get_row("SELECT 1 FROM images WHERE id = :cid", ["cid"=>$childID])) {
-            $database->execute("UPDATE images SET parent_id = :pid WHERE id = :cid", ["cid"=>$childID, "pid"=>$parentID]);
-            $database->execute("UPDATE images SET has_children = TRUE WHERE id = :pid", ["pid"=>$parentID]);
+        $results = $database->get_all_iterable("SELECT * FROM images WHERE parent_id = :pid ", ["pid"=>$image->id]);
+        $output = [];
+        foreach ($results as $result) {
+            if($result["id"]==$omit) {
+                continue;
+            }
+            $output[] = new Image($result);
         }
+        return $output;
     }
 
     private function remove_parent(int $imageID)
@@ -134,8 +166,23 @@ class Relationships extends Extension
 
         if ($parentID) {
             $database->execute("UPDATE images SET parent_id = NULL WHERE id = :iid", ["iid"=>$imageID]);
-            $database->execute("UPDATE images SET has_children = (SELECT * FROM (SELECT CASE WHEN COUNT(*) > 0 THEN 1 ELSE 0 END FROM images WHERE parent_id = :pid) AS sub)
-								WHERE id = :pid", ["pid"=>$parentID]);
+            $this->set_has_children($parentID);
         }
     }
+
+    private function set_has_children(int $parent_id)
+    {
+        global $database;
+
+        // Doesn't work on pgsql
+//        $database->execute("UPDATE images SET has_children = (SELECT * FROM (SELECT CASE WHEN COUNT(*) > 0 THEN 1 ELSE 0 END FROM images WHERE parent_id = :pid) AS sub)
+//								WHERE id = :pid", ["pid"=>$parentID]);
+
+        $database->execute(
+            "UPDATE images SET has_children = EXISTS (SELECT 1 FROM images WHERE parent_id = :pid) WHERE id = :pid",
+            ["pid"=>$parent_id]);
+    }
+
+
+
 }
diff --git a/ext/relatationships/test.php b/ext/relatationships/test.php
new file mode 100644
index 00000000..b486378a
--- /dev/null
+++ b/ext/relatationships/test.php
@@ -0,0 +1,192 @@
+<?php
+class RelationshipTest extends ShimmiePHPUnitTestCase
+{
+    public function testSetParent()
+    {
+        $this->log_in_as_user();
+
+        $image_id_1 = $this->post_image("tests/pbx_screenshot.jpg", "pbx");
+        $image_id_2 = $this->post_image("tests/bedroom_workshop.jpg", "pbx");
+        $image_id_3 = $this->post_image("tests/favicon.png", "pbx");
+
+        $image_1 = Image::by_id($image_id_1);
+        $image_2 = Image::by_id($image_id_2);
+        $image_3 = Image::by_id($image_id_3);
+
+        $this->assertNull($image_1->parent_id);
+        $this->assertNull($image_2->parent_id);
+        $this->assertNull($image_3->parent_id);
+        $this->assertFalse($image_1->has_children);
+        $this->assertFalse($image_2->has_children);
+        $this->assertFalse($image_3->has_children);
+
+        $this->get_page("post/view/$image_id_2");
+        $this->assert_title("Image $image_id_2: pbx");
+
+        $this->markTestIncomplete();
+
+        $this->set_field("tag_edit__parent", $image_id_1);
+        $this->click("Set");
+
+
+        $image_1 = Image::by_id($image_id_1);
+        $image_2 = Image::by_id($image_id_2);
+        $image_3 = Image::by_id($image_id_3);
+
+        $this->assertNull($image_1->parent_id);
+        $this->assertEquals($image_id_1,$image_2->parent_id);
+        $this->assertNull($image_3->parent_id);
+        $this->assertTrue($image_1->has_children);
+        $this->assertFalse($image_2->has_children);
+        $this->assertFalse($image_3->has_children);
+
+
+        // Test changing to a different parent
+
+        $this->get_page("post/view/$image_id_2");
+        $this->assert_title("Image $image_id_2: pbx");
+
+        $this->markTestIncomplete();
+
+        $this->set_field("tag_edit__parent", $image_id_3);
+        $this->click("Set");
+
+        $image_1 = Image::by_id($image_id_1);
+        $image_2 = Image::by_id($image_id_2);
+        $image_3 = Image::by_id($image_id_3);
+
+        $this->assertNull($image_1->parent_id);
+        $this->assertEquals($image_id_3,$image_2->parent_id);
+        $this->assertNull($image_3->parent_id);
+        $this->assertFalse($image_2->has_children);
+        $this->assertFalse($image_2->has_children);
+        $this->assertTrue($image_3->has_children);
+
+
+        // Test setting parent to none
+
+        $this->get_page("post/view/$image_id_2");
+        $this->assert_title("Image $image_id_2: pbx");
+
+        $this->markTestIncomplete();
+
+        $this->set_field("tag_edit__parent", "");
+        $this->click("Set");
+
+        $image_1 = Image::by_id($image_id_1);
+        $image_2 = Image::by_id($image_id_2);
+        $image_3 = Image::by_id($image_id_3);
+
+        $this->assertNull($image_1->parent_id);
+        $this->assertNull($image_2->parent_id);
+        $this->assertNull($image_3->parent_id);
+        $this->assertFalse($image_2->has_children);
+        $this->assertFalse($image_2->has_children);
+        $this->assertFalse($image_3->has_children);
+
+
+        $this->log_out();
+
+        $this->log_in_as_admin();
+        $this->delete_image($image_id_1);
+        $this->delete_image($image_id_2);
+        $this->delete_image($image_id_3);
+        $this->log_out();
+    }
+
+    public function testSetParentByTag()
+    {
+        $this->log_in_as_user();
+        $image_id_1 = $this->post_image("tests/pbx_screenshot.jpg", "pbx");
+        $image_id_2 = $this->post_image("tests/bedroom_workshop.jpg", "pbx");
+        $image_id_3 = $this->post_image("tests/favicon.png", "pbx");
+
+        $image_1 = Image::by_id($image_id_1);
+        $image_2 = Image::by_id($image_id_2);
+        $image_3 = Image::by_id($image_id_3);
+
+        $this->assertNull($image_1->parent_id);
+        $this->assertNull($image_2->parent_id);
+        $this->assertNull($image_3->parent_id);
+        $this->assertFalse($image_1->has_children);
+        $this->assertFalse($image_2->has_children);
+        $this->assertFalse($image_3->has_children);
+
+        // Test settings parent:#
+
+        $this->get_page("post/view/$image_id_2");
+        $this->assert_title("Image $image_id_2: pbx");
+
+        $this->markTestIncomplete();
+
+        $this->set_field("tag_edit__tags", "pbx parent:$image_id_1");
+        $this->click("Set");
+
+        $this->assert_title("Image $image_id_2: pbx");
+
+        $image_1 = Image::by_id($image_id_1);
+        $image_2 = Image::by_id($image_id_2);
+        $image_3 = Image::by_id($image_id_3);
+
+        $this->assertNull($image_1->parent_id);
+        $this->assertEquals($image_id_1,$image_2->parent_id);
+        $this->assertNull($image_3->parent_id);
+        $this->assertTrue($image_1->has_children);
+        $this->assertFalse($image_2->has_children);
+        $this->assertFalse($image_3->has_children);
+
+        // Test settings child:#
+
+        $this->get_page("post/view/$image_id_3");
+        $this->assert_title("Image $image_id_3: pbx");
+
+        $this->markTestIncomplete();
+
+        $this->set_field("tag_edit__tags", "pbx child:$image_id_1");
+        $this->click("Set");
+
+        $this->assert_title("Image $image_id_3: pbx");
+
+        $image_1 = Image::by_id($image_id_1);
+        $image_2 = Image::by_id($image_id_2);
+        $image_3 = Image::by_id($image_id_3);
+
+        $this->assertEquals($image_id_3,$image_1->parent_id);
+        $this->assertEquals($image_id_1,$image_2->parent_id);
+        $this->assertNull($image_3->parent_id);
+        $this->assertTrue($image_1->has_children);
+        $this->assertFalse($image_2->has_children);
+        $this->assertTrue($image_3->has_children);
+
+        // Test settings parent:none
+
+        $this->get_page("post/view/$image_id_1");
+        $this->assert_title("Image $image_id_1: pbx");
+
+        $this->markTestIncomplete();
+
+        $this->set_field("tag_edit__tags", "pbx parent:none");
+        $this->click("Set");
+
+        $this->assert_title("Image $image_id_1: pbx");
+
+        $image_1 = Image::by_id($image_id_1);
+        $image_2 = Image::by_id($image_id_2);
+        $image_3 = Image::by_id($image_id_3);
+
+        $this->assertNull($image_1->parent_id);
+        $this->assertEquals($image_id_1,$image_2->parent_id);
+        $this->assertNull($image_3->parent_id);
+        $this->assertTrue($image_1->has_children);
+        $this->assertFalse($image_2->has_children);
+        $this->assertFalse($image_3->has_children);
+
+        $this->log_out();
+
+        $this->log_in_as_admin();
+        $this->delete_image($image_id_1);
+        $this->delete_image($image_id_2);
+        $this->delete_image($image_id_3);
+        $this->log_out();
+    }
+}