https://github.com/ImageMagick/ImageMagick/issues/621

diff --git a/coders/png.c b/coders/png.c
index a3a84bc1cea5d460f7629937b5e7d0c90550475d..01007898a10f179da0ac4aa7afb19d19cffed1b6 100644 (file)
--- a/coders/png.c
+++ b/coders/png.c
@@ -2268,6 +2268,8 @@ static Image *ReadOnePNGImage(MngInfo *mng_info,
     }
 
   pixel_info=(MemoryInfo *) NULL;
+  quantum_scanline = (Quantum *) NULL;
+  quantum_info = (QuantumInfo *) NULL;
 
   if (setjmp(png_jmpbuf(ping)))
     {