diff --git a/coders/rgb.c b/coders/rgb.c
index 27cece4..7941ab7 100644
--- a/coders/rgb.c
+++ b/coders/rgb.c
@@ -132,12 +132,12 @@
     Open image file.
   */
   assert(image_info != (const ImageInfo *) NULL);
-  assert(image_info->signature == MagickSignature);
+  assert(image_info->signature == MagickCoreSignature);
   if (image_info->debug != MagickFalse)
     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
       image_info->filename);
   assert(exception != (ExceptionInfo *) NULL);
-  assert(exception->signature == MagickSignature);
+  assert(exception->signature == MagickCoreSignature);
   image=AcquireImage(image_info,exception);
   if ((image->columns == 0) || (image->rows == 0))
     ThrowReaderException(OptionError,"MustSpecifyImageSize");
@@ -1119,9 +1119,9 @@
     Allocate memory for pixels.
   */
   assert(image_info != (const ImageInfo *) NULL);
-  assert(image_info->signature == MagickSignature);
+  assert(image_info->signature == MagickCoreSignature);
   assert(image != (Image *) NULL);
-  assert(image->signature == MagickSignature);
+  assert(image->signature == MagickCoreSignature);
   if (image->debug != MagickFalse)
     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
   if (image_info->interlace != PartitionInterlace)