Set pixel cache to undefined if any resource limit is exceeded
MagickExport VirtualPixelMethod SetImageVirtualPixelMethod(Image *image,
  const VirtualPixelMethod virtual_pixel_method,ExceptionInfo *exception)
{
  assert(image != (const Image *) NULL);
  assert(image->signature == MagickCoreSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  return(SetPixelCacheVirtualMethod(image,virtual_pixel_method,exception));
}

MagickExport VirtualPixelMethod SetImageVirtualPixelMethod(Image *image,
  const VirtualPixelMethod virtual_pixel_method,ExceptionInfo *exception)
{
  assert(image != (const Image *) NULL);
  assert(image->signature == MagickCoreSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  return(SetPixelCacheVirtualMethod(image,virtual_pixel_method,exception));
}
