diff --git a/pdfio.vcxproj b/pdfio.vcxproj
index 7fc38b9..262e657 100644
--- a/pdfio.vcxproj
+++ b/pdfio.vcxproj
@@ -115,7 +115,7 @@
     <ClCompile>
       <WarningLevel>Level3</WarningLevel>
       <SDLCheck>true</SDLCheck>
-      <PreprocessorDefinitions>_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>HAVE_LIBPNG;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ConformanceMode>true</ConformanceMode>
     </ClCompile>
     <Link>
@@ -130,7 +130,7 @@
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <SDLCheck>true</SDLCheck>
-      <PreprocessorDefinitions>NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>HAVE_LIBPNG;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ConformanceMode>true</ConformanceMode>
     </ClCompile>
     <Link>
diff --git a/pdfio_native.nuspec b/pdfio_native.nuspec
index ca43085..1ce3ce1 100644
--- a/pdfio_native.nuspec
+++ b/pdfio_native.nuspec
@@ -17,6 +17,7 @@
         <tags>pdf file native</tags>
 	<dependencies>
 	    <dependency id="pdfio_native.redist" version="1.5.0" />
+	    <dependency id="libpng_native.redist" version="1.6.30" />
 	    <dependency id="zlib_native.redist" version="1.2.11" />
 	</dependencies>
     </metadata>
diff --git a/pdfio_native.redist.nuspec b/pdfio_native.redist.nuspec
index ba534b5..aa8e6cd 100644
--- a/pdfio_native.redist.nuspec
+++ b/pdfio_native.redist.nuspec
@@ -16,6 +16,7 @@
         <copyright>Copyright © 2019-2025 by Michael R Sweet</copyright>
         <tags>pdf file native</tags>
 	<dependencies>
+	    <dependency id="libpng_native.redist" version="1.6.30" />
 	    <dependency id="zlib_native.redist" version="1.2.11" />
 	</dependencies>
     </metadata>
diff --git a/runtests.bat b/runtests.bat
index ff7e87c..1cbf346 100644
--- a/runtests.bat
+++ b/runtests.bat
@@ -7,6 +7,8 @@
 
 :: Copy dependent DLLs to the named build directory
 echo Copying DLLs
+copy packages\libpng_native.redist.1.6.30\build\native\bin\x64\Debug\*.dll %1
+copy packages\libpng_native.redist.1.6.30\build\native\bin\x64\Release\*.dll %1
 copy packages\zlib_native.redist.1.2.11\build\native\bin\x64\Debug\*.dll %1
 copy packages\zlib_native.redist.1.2.11\build\native\bin\x64\Release\*.dll %1