diff --git a/msvc/caca-sharp.csproj b/msvc/caca-sharp.csproj
index 28a3795..51ce039 100755
--- a/msvc/caca-sharp.csproj
+++ b/msvc/caca-sharp.csproj
@@ -30,6 +30,7 @@
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Data" />
+    <Reference Include="System.Drawing" />
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
@@ -50,4 +51,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>
\ No newline at end of file
diff --git a/msvc/cucul-sharp.csproj b/msvc/cucul-sharp.csproj
index 5b3ecdd..610cfa1 100755
--- a/msvc/cucul-sharp.csproj
+++ b/msvc/cucul-sharp.csproj
@@ -29,6 +29,7 @@
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
+    <Reference Include="System.Drawing" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="..\csharp\Cucul.cs" />
@@ -42,4 +43,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>
\ No newline at end of file
diff --git a/msvc/test-csharp.csproj b/msvc/test-csharp.csproj
index 567354c..4bf13d7 100755
--- a/msvc/test-csharp.csproj
+++ b/msvc/test-csharp.csproj
@@ -49,4 +49,7 @@
       <Name>cucul-sharp</Name>
     </ProjectReference>
   </ItemGroup>
-</Project>
+  <ItemGroup>
+    <Reference Include="System.Drawing" />
+  </ItemGroup>
+</Project>
\ No newline at end of file