diff --git a/formwork/src/Images/Handler/WebpHandler.php b/formwork/src/Images/Handler/WebpHandler.php
index 38e89c42..3d1b8329 100644
--- a/formwork/src/Images/Handler/WebpHandler.php
+++ b/formwork/src/Images/Handler/WebpHandler.php
@@ -228,6 +228,10 @@ protected function setDataFromGdImage(GdImage $gdImage): void
     {
         imagesavealpha($gdImage, true);
 
+        if (!imageistruecolor($gdImage)) {
+            imagepalettetotruecolor($gdImage);
+        }
+
         ob_start();
 
         if (imagewebp($gdImage, null, $this->options['webpQuality']) === false) {