diff --git a/src/image_util.cpp b/src/image_util.cpp
index 291ae5beb..dc1fbbebe 100644
--- a/src/image_util.cpp
+++ b/src/image_util.cpp
@@ -86,6 +86,15 @@ std::string save_to_string(T const& image,
     return ss.str();
 }
 
+template <typename T>
+std::string save_to_string(T const& image,
+                           std::string const& type)
+{
+    std::ostringstream ss(std::ios::out|std::ios::binary);
+    save_to_stream(image, ss, type);
+    return ss.str();
+}
+
 template <typename T>
 void save_to_file(T const& image,
                   std::string const& filename,
@@ -428,6 +437,9 @@ template void save_to_file<image_data_32>(image_data_32 const&,
                                           std::string const&,
                                           rgba_palette const& palette);
 
+template std::string save_to_string<image_data_32>(image_data_32 const&,
+                                                   std::string const&);
+
 template std::string save_to_string<image_data_32>(image_data_32 const&,
                                                    std::string const&,
                                                    rgba_palette const& palette);
@@ -448,6 +460,9 @@ template void save_to_file<image_view<image_data_32> > (image_view<image_data_32
                                                         std::string const&,
                                                         rgba_palette const& palette);
    
+template std::string save_to_string<image_view<image_data_32> > (image_view<image_data_32> const&,
+                                                                 std::string const&);
+   
 template std::string save_to_string<image_view<image_data_32> > (image_view<image_data_32> const&,
                                                                  std::string const&,
                                                                  rgba_palette const& palette);