diff --git a/ext/upload/main.php b/ext/upload/main.php
index f62571b5..87721824 100644
--- a/ext/upload/main.php
+++ b/ext/upload/main.php
@@ -16,7 +16,9 @@
 class DataUploadEvent extends Event {
 	var $user, $tmpname, $metadata, $hash, $type, $image_id = -1;
 
-	public function DataUploadEvent($user, $tmpname, $metadata) {
+	public function DataUploadEvent(User $user, $tmpname, $metadata) {
+		assert(file_exists($tmpname));
+
 		$this->user = $user;
 		$this->tmpname = $tmpname;
 
diff --git a/ext/view/main.php b/ext/view/main.php
index bec26a02..33cedd7b 100644
--- a/ext/view/main.php
+++ b/ext/view/main.php
@@ -45,7 +45,7 @@ class ImageInfoBoxBuildingEvent extends Event {
 class ImageInfoSetEvent extends Event {
 	var $image;
 
-	public function ImageInfoSetEvent($image) {
+	public function ImageInfoSetEvent(Image $image) {
 		$this->image = $image;
 	}
 }