diff --git a/src/pixie/fileformats/png.nim b/src/pixie/fileformats/png.nim
index 67c3b62..2db254f 100644
--- a/src/pixie/fileformats/png.nim
+++ b/src/pixie/fileformats/png.nim
@@ -437,9 +437,10 @@ proc encodePng*(
       raise newException(PixieError, "Invalid PNG number of channels")
 
   let data = cast[ptr UncheckedArray[uint8]](data)
+  const signature = [137.uint8, 80, 78, 71, 13, 10, 26, 10]
 
   # Add the PNG file signature
-  result.add([137.uint8, 80, 78, 71, 13, 10, 26, 10])
+  result.add(signature)
 
   # Add IHDR
   result.addUint32(13.uint32.swap())