diff --git a/TODO b/TODO
index 9c996a5f..d9fdc0a4 100644
--- a/TODO
+++ b/TODO
@@ -4,7 +4,6 @@ first major release.
 - autocomplete: don't show items that are already used in tag list (unsure)
 - posts/upload: ability to paste many urls (unsure)
 - posts/listing: add buttons for toggling safety
-- posts: fix empty edit snapshots when changing only thumbnail content
 - users: add user-configurable "about me" (should support Markdown)
 - tags: refresh tags.json when editing post
 - tags: add tag merging
diff --git a/src/Services/PostSnapshotProvider.php b/src/Services/PostSnapshotProvider.php
index d850abd2..b791e844 100644
--- a/src/Services/PostSnapshotProvider.php
+++ b/src/Services/PostSnapshotProvider.php
@@ -34,24 +34,27 @@ class PostSnapshotProvider
 			'featured' => $isFeatured,
 
 			'tags' =>
-				array_map(
+				array_values(array_map(
 					function ($tag)
 					{
 						return $tag->getName();
 					},
-					$post->getTags()),
+					$post->getTags())),
 
 			'relations' =>
-				array_map(
+				array_values(array_map(
 					function ($post)
 					{
 						return $post->getId();
 					},
-					$post->getRelatedPosts()),
+					$post->getRelatedPosts())),
 
 			'flags' => $flags,
 		];
 
+		sort($data['tags']);
+		sort($data['relations']);
+
 		$snapshot = $this->getPostSnapshot($post);
 		$snapshot->setOperation(Snapshot::OPERATION_CHANGE);
 		$snapshot->setData($data);