https://github.com/ImageMagick/ImageMagick/pull/1325

diff --git a/MagickCore/fx.c b/MagickCore/fx.c
index 0658d09138f3a11661a8638b1d6c43f7fd2246a1..a6517a83e27442924948ab8c6091be1c486c5909 100644 (file)
--- a/MagickCore/fx.c
+++ b/MagickCore/fx.c
@@ -3135,6 +3135,8 @@ MagickExport Image *FxImage(const Image *image,const char *expression,
   assert(image->signature == MagickCoreSignature);
   if (image->debug != MagickFalse)
     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
+  if (expression == (const char *) NULL)
+    return(CloneImage(image,0,0,MagickTrue,exception));
   fx_info=AcquireFxThreadSet(image,expression,exception);
   if (fx_info == (FxInfo **) NULL)
     return((Image *) NULL);