diff --git a/phpBB/includes/functions_posting.php b/phpBB/includes/functions_posting.php
index dd6313f666..a3b743777f 100644
--- a/phpBB/includes/functions_posting.php
+++ b/phpBB/includes/functions_posting.php
@@ -659,6 +659,10 @@ function create_thumbnail($source, $destination, $mimetype)
 				case IMG_WBMP:
 					$image = @imagecreatefromwbmp($source);
 				break;
+
+				case IMG_WEBP:
+					$image = @imagecreatefromwebp($source);
+				break;
 			}
 
 			if (empty($image))
@@ -710,6 +714,10 @@ function create_thumbnail($source, $destination, $mimetype)
 				case IMG_WBMP:
 					imagewbmp($new_image, $destination);
 				break;
+
+				case IMG_WEBP:
+					imagewebp($new_image, $destination);
+				break;
 			}
 
 			imagedestroy($new_image);