diff --git a/openalpr-net/openalpr-net.vcxproj b/openalpr-net/openalpr-net.vcxproj
index 2088375..5f37063 100644
--- a/openalpr-net/openalpr-net.vcxproj
+++ b/openalpr-net/openalpr-net.vcxproj
@@ -74,6 +74,7 @@
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Data" />
+    <Reference Include="System.Drawing" />
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>