diff --git a/MiniEngine.cpp b/MiniEngine.cpp
index 014e917..ae58468 100644
--- a/MiniEngine.cpp
+++ b/MiniEngine.cpp
@@ -2114,7 +2114,7 @@ namespace MiniEngine
     std::tuple<int,int,int> SDLSystem::GetIMGLinkedVersion()
     {
         const SDL_version* ptr=IMG_Linked_Version();
-        return std::make_tuple();
+        return std::make_tuple(ptr->major,ptr->minor,ptr->patch);
     }
 
     //static
diff --git a/MiniEngine_Test.h b/MiniEngine_Test.h
index b05319b..f574c82 100644
--- a/MiniEngine_Test.h
+++ b/MiniEngine_Test.h
@@ -13,7 +13,8 @@ void GetMD5Raw(unsigned char* buffer,unsigned int bufferLen,unsigned char* outbu
 
 int GetCRC32(unsigned char* buffer,unsigned int bufferLen,uint32_t& out_CRCResult);
 
-int CompareSurface(const Surface& surface1,const Surface& surface2,int allowableError);
+/// Compare two surfaces. Currently, Surface::getRawPointer() does not has constant attribute.
+int CompareSurface(Surface& surface1,Surface& surface2,int allowableError);
 
 class UniRandom
 {