diff --git a/reference/image/functions/imagecreatefromwbmp.xml b/reference/image/functions/imagecreatefromwbmp.xml
index 30d8003624..20620df519 100644
--- a/reference/image/functions/imagecreatefromwbmp.xml
+++ b/reference/image/functions/imagecreatefromwbmp.xml
@@ -67,7 +67,7 @@ function LoadWBMP($imgname)
     return $im;
 }
 
-header('Content-Type: ' . image_type_to_mime_type(IMAGETYPE_WBMP));
+header('Content-type: image/vnd.wap.wbmp');
 
 $img = LoadWBMP('bogus.image');