diff --git a/.phan/stubs/misc.php b/.phan/stubs/misc.php
index ee331871a..186fc1e0f 100644
--- a/.phan/stubs/misc.php
+++ b/.phan/stubs/misc.php
@@ -8,4 +8,7 @@
  * @license      MIT
  */
 
-#class GdImage{}
+// looks like some linux distros don't support AVIF?? (Ubuntu 25.04 PHP 8.4.5-ondrej)
+function imageavif(\GdImage $image, mixed $file=null, int $quality=-1, int $speed=-1):bool{
+	return true;
+}