diff --git a/BMap/BMExports.cpp b/BMap/BMExports.cpp
index ac4e6b0..ce3c081 100644
--- a/BMap/BMExports.cpp
+++ b/BMap/BMExports.cpp
@@ -357,14 +357,14 @@ bool BM3dEntity_SetCurrentMesh(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid, L
 	return true;
 }
 
-bool BM3dEntity_GetVisivility(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid) {
+bool BM3dEntity_GetVisibility(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid) {
 	auto obj = CheckCK3dObject(bmfile, objid);
 	if (obj == nullptr) return false;
 
 	return obj->IsVisible();
 }
 
-bool BM3dEntity_SetVisivility(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid, bool is_visible) {
+bool BM3dEntity_SetVisibility(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid, bool is_visible) {
 	auto obj = CheckCK3dObject(bmfile, objid);
 	if (obj == nullptr) return false;
 
diff --git a/BMap/BMExports.hpp b/BMap/BMExports.hpp
index 2ae1567..627e6a5 100644
--- a/BMap/BMExports.hpp
+++ b/BMap/BMExports.hpp
@@ -16,6 +16,14 @@ Design Note:
 
 */
 
+// some macro to help export function define.
+
+#define BMPARAM_FILE_DECL BMap::BMFile* bmfile
+#define BMPARAM_MESHTRANS_DECL BMap::BMMeshTransition* trans
+#define BMPARAM_OBJECT_DECL BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid
+#define BMPARAM_IN(_t, _name) _t _name
+#define BMPARAM_OUT(_t, _name) _t* _name
+
 #pragma region Init / Dispose
 
 LIBCMO_EXPORT void BMInit();
@@ -87,6 +95,13 @@ LIBCMO_EXPORT LibCmo::CK2::CK_ID BMGroup_GetObject(BMap::BMFile* bmfile, LibCmo:
 
 #pragma region CKTexture
 
+LIBCMO_EXPORT bool BMTexture_PrepareSlotCount();
+LIBCMO_EXPORT LibCmo::CKSTRING BMTexture_GetSlotFileName();
+LIBCMO_EXPORT bool BMTexture_LoadImage(LibCmo::CKSTRING filename);
+LIBCMO_EXPORT bool BMTexture_SaveImage(LibCmo::CKSTRING filename);
+LIBCMO_EXPORT LibCmo::CK2::CK_TEXTURE_SAVEOPTIONS BMTexture_GetSaveOptions();
+LIBCMO_EXPORT bool BMTexture_SetSaveOptions(LibCmo::CK2::CK_TEXTURE_SAVEOPTIONS saveopt);
+
 #pragma endregion
 
 #pragma region CKMaterial
@@ -114,7 +129,7 @@ LIBCMO_EXPORT CStyleVxMatrix BM3dEntity_GetWorldMatrix(BMap::BMFile* bmfile, Lib
 LIBCMO_EXPORT bool BM3dEntity_SetWorldMatrix(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid, CStyleVxMatrix mat);
 LIBCMO_EXPORT LibCmo::CK2::CK_ID BM3dEntity_GetCurrentMesh(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid);
 LIBCMO_EXPORT bool BM3dEntity_SetCurrentMesh(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid, LibCmo::CK2::CK_ID meshid);
-LIBCMO_EXPORT bool BM3dEntity_GetVisivility(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid);
-LIBCMO_EXPORT bool BM3dEntity_SetVisivility(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid, bool is_visible);
+LIBCMO_EXPORT bool BM3dEntity_GetVisibility(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid);
+LIBCMO_EXPORT bool BM3dEntity_SetVisibility(BMap::BMFile* bmfile, LibCmo::CK2::CK_ID objid, bool is_visible);
 
 #pragma endregion
diff --git a/LibCmo/CK2/CKBitmapData.cpp b/LibCmo/CK2/CKBitmapData.cpp
index 22502a2..77ba414 100644
--- a/LibCmo/CK2/CKBitmapData.cpp
+++ b/LibCmo/CK2/CKBitmapData.cpp
@@ -560,7 +560,10 @@ namespace LibCmo::CK2 {
 		// get extension of file. then get corresponding reader
 		XContainer::XString ext(filename);
 		m_Context->GetPathManager()->GetExtension(ext);
-		auto reader = DataHandlers::CKBitmapHandler::GetBitmapHandlerWrapper(CKFileExtension(ext.c_str()), CKGUID());
+		auto reader = DataHandlers::CKBitmapHandler::GetBitmapHandlerWrapper(
+			CKFileExtension(ext.c_str()),
+			CKGUID()
+		);
 		if (reader == nullptr) return false;
 
 		// get desc and read data
@@ -621,9 +624,9 @@ namespace LibCmo::CK2 {
 
 	CKSTRING CKBitmapData::GetSlotFileName(CKDWORD slot) const {
 		if (slot >= m_Slots.size()) return nullptr;
-		// return nullptr if no corresponding filename
-		if (m_Slots[slot].m_FileName.empty()) return nullptr;
-		else return m_Slots[slot].m_FileName.c_str();
+
+		// return nullptr if corresponding filename is empty to indicate there is no binding filename
+		return XContainer::NSXString::ToCKSTRING(m_Slots[slot].m_FileName);
 	}
 
 	CKDWORD CKBitmapData::GetWidth() const {
diff --git a/LibCmo/CK2/CKContext.cpp b/LibCmo/CK2/CKContext.cpp
index 915b9bd..7857dc2 100644
--- a/LibCmo/CK2/CKContext.cpp
+++ b/LibCmo/CK2/CKContext.cpp
@@ -270,6 +270,8 @@ namespace LibCmo::CK2 {
 
 		va_end(argptr);
 
+		// use c_str(), not XContainer::NSXString::ToCKSTRING because we want make sure this paramter is not nullptr.
+		// we always output a valid C style string, even if no chars need to write.
 		m_OutputCallback(result.c_str());
 	}
 
diff --git a/LibCmo/CK2/ObjImpls/CKTexture.cpp b/LibCmo/CK2/ObjImpls/CKTexture.cpp
index ea7f9cd..035a672 100644
--- a/LibCmo/CK2/ObjImpls/CKTexture.cpp
+++ b/LibCmo/CK2/ObjImpls/CKTexture.cpp
@@ -1,5 +1,7 @@
 #include "CKTexture.hpp"
 #include "../CKStateChunk.hpp"
+#include "../CKContext.hpp"
+#include "../MgrImpls/CKPathManager.hpp"
 
 namespace LibCmo::CK2::ObjImpls {
 
@@ -330,6 +332,24 @@ namespace LibCmo::CK2::ObjImpls {
 		return m_ImageHost;
 	}
 
+	bool CKTexture::LoadImage(CKSTRING filename, CKDWORD slot) {
+		// check file name
+		if (filename == nullptr) return false;
+		// check slot
+		if (slot >= m_ImageHost.GetSlotCount()) return false;
+
+		// resolve file name first
+		XContainer::XString filepath;
+		XContainer::NSXString::FromCKSTRING(filepath, filename);
+		if (!m_Context->GetPathManager()->ResolveFileName(filepath)) return false;
+
+		// try loading image
+		if (!m_ImageHost.LoadImage(XContainer::NSXString::ToCKSTRING(filepath), slot)) return false;
+
+		// sync file name
+		return m_ImageHost.SetSlotFileName(slot, XContainer::NSXString::ToCKSTRING(filepath));
+	}
+
 	bool CKTexture::IsUseMipmap() const {
 		return m_UseMipMap;
 	}
diff --git a/LibCmo/CK2/ObjImpls/CKTexture.hpp b/LibCmo/CK2/ObjImpls/CKTexture.hpp
index ed15f00..1ccebc8 100644
--- a/LibCmo/CK2/ObjImpls/CKTexture.hpp
+++ b/LibCmo/CK2/ObjImpls/CKTexture.hpp
@@ -21,6 +21,14 @@ namespace LibCmo::CK2::ObjImpls {
 
 		CKBitmapData& GetUnderlyingData();
 
+		/**
+		 * @brief A wrapper of underlying CKBitmapData::LoadImage. Not only load image, but also set file name.
+		 * @param filename[in] File name of loading image.
+		 * @param slot[in] The slot that image will be loaded into.
+		 * @return True if success.
+		*/
+		bool LoadImage(CKSTRING filename, CKDWORD slot);
+
 		bool IsUseMipmap() const;
 		void UseMipmap(bool isUse);
 		CKDWORD GetMipmapLevel() const;