diff --git a/vtkm/rendering/EncodePNG.cxx b/vtkm/rendering/EncodePNG.cxx
index b3004e5ed..11dbb14ed 100644
--- a/vtkm/rendering/EncodePNG.cxx
+++ b/vtkm/rendering/EncodePNG.cxx
@@ -29,7 +29,8 @@ vtkm::UInt32 EncodePNG(std::vector<unsigned char> const& image,
 {
   // The default is 8 bit RGBA; does anyone care to have more options?
   // We can certainly add them in a backwards-compatible way if need be.
-  vtkm::UInt32 error = vtkm::png::lodepng::encode(output_png, image, width, height);
+  vtkm::UInt32 error = vtkm::png::lodepng::encode(
+    output_png, image, static_cast<unsigned int>(width), static_cast<unsigned int>(height));
   if (error)
   {
     VTKM_LOG_S(vtkm::cont::LogLevel::Error,