https://www.imagemagick.org/discourse-server/viewtopic.php?f=2&t=30043

diff --git a/MagickCore/constitute.c b/MagickCore/constitute.c
index 79a5a8030cd58f33c4f83a52bf1aa4cba8559047..e9b45c6d1fbe8df2af1e42376c53baddf67c5411 100644 (file)
--- a/MagickCore/constitute.c
+++ b/MagickCore/constitute.c
@@ -227,6 +227,7 @@ MagickExport Image *PingImage(const ImageInfo *image_info,
   if (image != (Image *) NULL)
     {
       ResetTimer(&image->timer);
+      InitializePixelChannelMap(image);
       if (ping_info->verbose != MagickFalse)
         (void) IdentifyImage(image,stdout,MagickFalse,exception);
     }