https://github.com/ImageMagick/ImageMagick/issues/1586

magick/statistic.c

@@ -149,8 +149,11 @@ static MagickPixelPacket **DestroyPixelThreadSet(MagickPixelPacket **pixels)
   return(pixels);
 }
 
-static MagickPixelPacket **AcquirePixelThreadSet(const Image *image)
+static MagickPixelPacket **AcquirePixelThreadSet(const Image *images)
 {
+  const Image
+    *next;
+
   MagickPixelPacket
     **pixels;
 
@@ -159,6 +162,7 @@ static MagickPixelPacket **AcquirePixelThreadSet(const Image *image)
     j;
 
   size_t
+    columns,
     number_threads;
 
   number_threads=(size_t) GetMagickResourceLimit(ThreadResource);
@@ -167,14 +171,17 @@ static MagickPixelPacket **AcquirePixelThreadSet(const Image *image)
   if (pixels == (MagickPixelPacket **) NULL)
     return((MagickPixelPacket **) NULL);
   (void) memset(pixels,0,number_threads*sizeof(*pixels));
+  columns=images->columns;
+  for (next=images; next != (Image *) NULL; next=next->next)
+    columns=MagickMax(next->columns,columns);
   for (i=0; i < (ssize_t) number_threads; i++)
   {
-    pixels[i]=(MagickPixelPacket *) AcquireQuantumMemory(image->columns,
+    pixels[i]=(MagickPixelPacket *) AcquireQuantumMemory(columns,
       sizeof(**pixels));
     if (pixels[i] == (MagickPixelPacket *) NULL)
       return(DestroyPixelThreadSet(pixels));
-    for (j=0; j < (ssize_t) image->columns; j++)
-      GetMagickPixelPacket(image,&pixels[i][j]);
+    for (j=0; j < (ssize_t) columns; j++)
+      GetMagickPixelPacket(images,&pixels[i][j]);
   }
   return(pixels);
 }