diff --git a/LibCmo/CK2/CKBitmapData.cpp b/LibCmo/CK2/CKBitmapData.cpp
new file mode 100644
index 0000000..b3ad2cc
--- /dev/null
+++ b/LibCmo/CK2/CKBitmapData.cpp
@@ -0,0 +1,9 @@
+#include "CKBitmapData.hpp"
+
+namespace LibCmo::CK2 {
+
+	CKBitmapData::CKBitmapData() {}
+
+	CKBitmapData::~CKBitmapData() {}
+
+}
diff --git a/LibCmo/CK2/CKBitmapData.hpp b/LibCmo/CK2/CKBitmapData.hpp
new file mode 100644
index 0000000..69d4eeb
--- /dev/null
+++ b/LibCmo/CK2/CKBitmapData.hpp
@@ -0,0 +1,16 @@
+#pragma once
+
+#include "../VTAll.hpp"
+
+namespace LibCmo::CK2 {
+
+	class CKBitmapData {
+	public:
+		CKBitmapData();
+		~CKBitmapData();
+
+	protected:
+
+	};
+
+}
diff --git a/LibCmo/CK2/CKStructs.hpp b/LibCmo/CK2/CKStructs.hpp
new file mode 100644
index 0000000..55da193
--- /dev/null
+++ b/LibCmo/CK2/CKStructs.hpp
@@ -0,0 +1,79 @@
+#pragma once
+
+#include "CKGlobals.hpp"
+
+namespace LibCmo::CK2 {
+	
+	// a stupid forward decl to remove something
+	/**
+	 * @brief Storage class for filename extensions
+	*/
+	class CKFileExtension {
+	public:
+		CKFileExtension() : m_Data() {
+			std::memset(m_Data, 0, c_DataLen);
+		}
+		CKFileExtension(CKSTRING s) : CKFileExtension() {
+			SetExt(s);
+		}
+		CKFileExtension(const CKFileExtension& rhs) : CKFileExtension() {
+			std::memcpy(m_Data, rhs.m_Data, c_DataLen);
+		}
+		CKFileExtension(CKFileExtension&& rhs) : CKFileExtension() {
+			std::memmove(m_Data, rhs.m_Data, c_DataLen);
+			std::memset(rhs.m_Data, 0, c_DataLen);
+		}
+		CKFileExtension& operator=(const CKFileExtension& rhs) {
+			std::memcpy(m_Data, rhs.m_Data, c_DataLen);
+			return *this;
+		}
+		CKFileExtension& operator=(CKFileExtension&& rhs) {
+			std::memmove(m_Data, rhs.m_Data, c_DataLen);
+			std::memset(rhs.m_Data, 0, c_DataLen);
+			return *this;
+		}
+
+		void SetExt(CKSTRING s) {
+			if (s == nullptr) {
+				m_Data[0] = '\0';
+			} else {
+				if (s[0] == '.') ++s;	// skip dot
+				size_t len = std::strlen(s);
+				if (len > (c_DataLen - 1)) len = c_DataLen - 1;
+				std::memcpy(m_Data, s, len);
+			}
+		}
+
+		CKSTRING GetExt() const {
+			return m_Data;
+		}
+
+		bool operator==(const CKFileExtension& rhs) const {
+			return CKStrEqualI(m_Data, rhs.m_Data);
+		}
+
+	protected:
+		static const size_t c_DataLen = 4u;
+		CKCHAR m_Data[c_DataLen];
+	};
+	
+	/**
+	 * The struct describe the bitmap handler's infomation,
+	 * including its GUID and supported file extension.
+	 * This struct also will store some parameters related to bitmap handler,
+	 * such as jpeg compress level and etc. But currently there are no
+	 * such parameters.
+	*/
+	class CKBitmapProperties {
+	public:
+		CKBitmapProperties() :
+			m_ReaderGuid(), m_Ext() {}
+		CKBitmapProperties(const CKGUID& guid, CKSTRING ext) :
+			m_ReaderGuid(guid), m_Ext(ext) {}
+		LIBCMO_DEFAULT_COPY_MOVE(CKBitmapProperties);
+
+		CKGUID m_ReaderGuid; /**< CKGUID that uniquely identifies the reader that created this properties structure */
+		CKFileExtension m_Ext; /**< File Extension of the image being described by this structure */
+	};
+
+}
diff --git a/LibCmo/CK2/CKTypes.hpp b/LibCmo/CK2/CKTypes.hpp
index 2c1fa86..688880b 100644
--- a/LibCmo/CK2/CKTypes.hpp
+++ b/LibCmo/CK2/CKTypes.hpp
@@ -266,7 +266,8 @@ namespace LibCmo::CK2 {
 	class CKObjectArray;
 	class CKObjectDeclaration;
 	//class CKContext;
-	//struct CKBitmapProperties;
+	class CKBitmapProperties;
+	class CKFileExtension;
 	class CKVertexBuffer;
 
 	//--- Managers
@@ -366,74 +367,4 @@ namespace LibCmo::CK2 {
 		}
 	};
 
-	/**
-	 * @brief Storage class for filename extensions
-	*/
-	class CKFileExtension {
-	public:
-		CKFileExtension() : m_Data() {
-			std::memset(m_Data, 0, c_DataLen);
-		}
-		CKFileExtension(CKSTRING s) : CKFileExtension() {
-			SetExt(s);
-		}
-		CKFileExtension(const CKFileExtension& rhs) : CKFileExtension() {
-			std::memcpy(m_Data, rhs.m_Data, c_DataLen);
-		}
-		CKFileExtension(CKFileExtension&& rhs) : CKFileExtension() {
-			std::memmove(m_Data, rhs.m_Data, c_DataLen);
-			std::memset(rhs.m_Data, 0, c_DataLen);
-		}
-		CKFileExtension& operator=(const CKFileExtension& rhs) {
-			std::memcpy(m_Data, rhs.m_Data, c_DataLen);
-		}
-		CKFileExtension& operator=(CKFileExtension&& rhs) {
-			std::memmove(m_Data, rhs.m_Data, c_DataLen);
-			std::memset(rhs.m_Data, 0, c_DataLen);
-		}
-
-		void SetExt(CKSTRING s) {
-			if (s == nullptr) {
-				m_Data[0] = '\0';
-			} else {
-				if (s[0] == '.') ++s;	// skip dot
-				size_t len = std::strlen(s);
-				if (len > (c_DataLen - 1)) len = c_DataLen - 1;
-				std::memcpy(m_Data, s, len);
-			}
-		}
-
-		CKSTRING GetExt() const {
-			return m_Data;
-		}
-
-		bool operator==(const CKFileExtension& rhs) const {
-			return CKStrEqualI(m_Data, rhs.m_Data);
-		}
-
-	protected:
-		static const size_t c_DataLen = 4u;
-		CKCHAR m_Data[c_DataLen];
-	};
-	
-	/**
-	 * The struct describe the bitmap handler's infomation,
-	 * including its GUID and supported file extension.
-	 * This struct also will store some parameters related to bitmap handler,
-	 * such as jpeg compress level and etc. But currently there are no
-	 * such parameters.
-	*/
-	class CKBitmapProperties {
-	public:
-		CKBitmapProperties() :
-			m_ReaderGuid(), m_Ext() {}
-		CKBitmapProperties(const CKGUID& guid, CKSTRING ext) :
-			m_ReaderGuid(guid), m_Ext(ext) {}
-		LIBCMO_DEFAULT_COPY_MOVE(CKBitmapProperties);
-
-		CKGUID m_ReaderGuid; /**< CKGUID that uniquely identifies the reader that created this properties structure */
-		CKFileExtension m_Ext; /**< File Extension of the image being described by this structure */
-	};
-
-
 }
diff --git a/LibCmo/CK2/DataHandlers/CKBitmapHandler.cpp b/LibCmo/CK2/DataHandlers/CKBitmapHandler.cpp
index 49db592..5e5fcd6 100644
--- a/LibCmo/CK2/DataHandlers/CKBitmapHandler.cpp
+++ b/LibCmo/CK2/DataHandlers/CKBitmapHandler.cpp
@@ -178,7 +178,7 @@ namespace LibCmo::CK2::DataHandlers {
 		// write data
 		MemorySaveContext* ctx = new MemorySaveContext(memory);
 		int ret = oper(
-			&FileWriteFunction, ctx,
+			&MemoryWriteFunction, ctx,
 			static_cast<int>(write_image->GetWidth()), static_cast<int>(write_image->GetHeight()),
 			4, data	// 4 == RGBA8888
 		);
@@ -208,11 +208,11 @@ namespace LibCmo::CK2::DataHandlers {
 	}
 
 	bool CKBitmapBMPHandler::ReadFile(CKSTRING u8filename, VxMath::VxImageDescEx* read_image) {
-		StbReadFile(u8filename, read_image);
+		return StbReadFile(u8filename, read_image);
 	}
 
 	bool CKBitmapBMPHandler::ReadMemory(const void* memory, CKDWORD size, VxMath::VxImageDescEx* read_image) {
-		StbReadMemory(memory, size, read_image);
+		return StbReadMemory(memory, size, read_image);
 	}
 
 	bool CKBitmapBMPHandler::SaveFile(CKSTRING u8filename, const VxMath::VxImageDescEx* write_image, const CKBitmapProperties& codec_param) {
@@ -245,11 +245,11 @@ namespace LibCmo::CK2::DataHandlers {
 	}
 
 	bool CKBitmapTGAHandler::ReadFile(CKSTRING u8filename, VxMath::VxImageDescEx* read_image) {
-		StbReadFile(u8filename, read_image);
+		return StbReadFile(u8filename, read_image);
 	}
 
 	bool CKBitmapTGAHandler::ReadMemory(const void* memory, CKDWORD size, VxMath::VxImageDescEx* read_image) {
-		StbReadMemory(memory, size, read_image);
+		return StbReadMemory(memory, size, read_image);
 	}
 
 	bool CKBitmapTGAHandler::SaveFile(CKSTRING u8filename, const VxMath::VxImageDescEx* write_image, const CKBitmapProperties& codec_param) {
diff --git a/LibCmo/CK2/MgrImpls/CKPathManager.cpp b/LibCmo/CK2/MgrImpls/CKPathManager.cpp
index 6904e34..28b187e 100644
--- a/LibCmo/CK2/MgrImpls/CKPathManager.cpp
+++ b/LibCmo/CK2/MgrImpls/CKPathManager.cpp
@@ -49,7 +49,7 @@ namespace LibCmo::CK2::MgrImpls {
 	}
 
 	bool CKPathManager::AddPath(CKSTRING u8path) {
-		if (u8path == nullptr) return;
+		if (u8path == nullptr) return false;
 		std::filesystem::path newpath;
 		EncodingHelper::U8PathToStdPath(newpath, u8path);
 		if (std::filesystem::is_directory(newpath)) {
@@ -86,7 +86,7 @@ namespace LibCmo::CK2::MgrImpls {
 		// test in temp folder
 		auto tempfile = m_TempFolder / filepath;
 		if (std::filesystem::is_regular_file(tempfile)) {
-			EncodingHelper::StdPathToU8Path(u8_filename, combinedpath);
+			EncodingHelper::StdPathToU8Path(u8_filename, tempfile);
 			return true;
 		}
 
diff --git a/LibCmo/LibCmo.vcxproj b/LibCmo/LibCmo.vcxproj
index af85d3c..fbc7aac 100644
--- a/LibCmo/LibCmo.vcxproj
+++ b/LibCmo/LibCmo.vcxproj
@@ -175,6 +175,7 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClCompile Include="CK2\CKBitmapData.cpp" />
     <ClCompile Include="CK2\CKFileOthers.cpp" />
     <ClCompile Include="CK2\CKFileWriter.cpp" />
     <ClCompile Include="CK2\CKGlobals.cpp" />
@@ -199,11 +200,13 @@
     <ClCompile Include="XContainer\XBitArray.cpp" />
   </ItemGroup>
   <ItemGroup>
+    <ClInclude Include="CK2\CKBitmapData.hpp" />
     <ClInclude Include="CK2\CKDefines.hpp" />
     <ClInclude Include="CK2\CKEnums.hpp" />
     <ClInclude Include="CK2\CKFile.hpp" />
     <ClInclude Include="CK2\CKGlobals.hpp" />
     <ClInclude Include="CK2\CKIdentifiers.hpp" />
+    <ClInclude Include="CK2\CKStructs.hpp" />
     <ClInclude Include="CK2\DataHandlers\CKBitmapHandler.hpp" />
     <ClInclude Include="CK2\MgrImpls\CKBaseManager.hpp" />
     <ClInclude Include="CK2\CKContext.hpp" />
diff --git a/LibCmo/LibCmo.vcxproj.filters b/LibCmo/LibCmo.vcxproj.filters
index f5415e4..7b4d72c 100644
--- a/LibCmo/LibCmo.vcxproj.filters
+++ b/LibCmo/LibCmo.vcxproj.filters
@@ -117,6 +117,9 @@
     <ClCompile Include="VxMath\VxMath.cpp">
       <Filter>Sources\VxMath</Filter>
     </ClCompile>
+    <ClCompile Include="CK2\CKBitmapData.cpp">
+      <Filter>Sources\CK2</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="VTUtils.hpp">
@@ -203,5 +206,11 @@
     <ClInclude Include="CK2\DataHandlers\CKBitmapHandler.hpp">
       <Filter>Headers\CK2\DataHandlers</Filter>
     </ClInclude>
+    <ClInclude Include="CK2\CKStructs.hpp">
+      <Filter>Headers\CK2</Filter>
+    </ClInclude>
+    <ClInclude Include="CK2\CKBitmapData.hpp">
+      <Filter>Headers\CK2</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/LibCmo/VTAll.hpp b/LibCmo/VTAll.hpp
index d7ff244..77083a1 100644
--- a/LibCmo/VTAll.hpp
+++ b/LibCmo/VTAll.hpp
@@ -21,6 +21,7 @@ Except the file listed in there, they should include "VTUtils.hpp" first.
 #include "CK2/CKEnums.hpp"	// All CK used enums except CKStateChunk identifiers.
 #include "CK2/CKIdentifiers.hpp"	// CKStateChunk identifiers.
 #include "CK2/CKGlobals.hpp"	// CK global functions, such as CKUnPack and etc.
+#include "CK2/CKStructs.hpp"	// Some essential and useful classes + structs.
 
 #include "VxMath/VxEnums.hpp"
 #include "VxMath/VxTypes.hpp"