diff --git a/modules/gallery/helpers/legal_file.php b/modules/gallery/helpers/legal_file.php
index bb939a06..bb84effb 100644
--- a/modules/gallery/helpers/legal_file.php
+++ b/modules/gallery/helpers/legal_file.php
@@ -39,7 +39,7 @@ class legal_file_Core {
       $types_by_extension_wrapper = new stdClass();
       $types_by_extension_wrapper->types_by_extension = array(
         "jpg" => "image/jpeg", "jpeg" => "image/jpeg", "gif" => "image/gif", "png" => "image/png",
-        "webp" => "image/webp");
+        "webp" => "image/webp", "avif" => "image/avif");
       module::event("photo_types_by_extension", $types_by_extension_wrapper);
       foreach (self::$blacklist as $key) {
         unset($types_by_extension_wrapper->types_by_extension[$key]);
diff --git a/system/libraries/Image.php b/system/libraries/Image.php
index 6e646e86..929f216a 100644
--- a/system/libraries/Image.php
+++ b/system/libraries/Image.php
@@ -32,6 +32,7 @@ class Image_Core {
 		IMAGETYPE_JPEG => 'jpg',
 		IMAGETYPE_PNG => 'png',
 		IMAGETYPE_WEBP => 'webp',
+		IMAGETYPE_AVIF => 'avif',
 		IMAGETYPE_TIFF_II => 'tiff',
 		IMAGETYPE_TIFF_MM => 'tiff',
 	);