diff --git a/include/nana/paint/graphics.hpp b/include/nana/paint/graphics.hpp
index 17a31491..ad2c8a6c 100644
--- a/include/nana/paint/graphics.hpp
+++ b/include/nana/paint/graphics.hpp
@@ -131,7 +131,10 @@ namespace nana
 			void setsta();      ///<  	Clears the status if the graphics object had been changed
 			void set_changed();
 			void release();
-			void save_as_file(const char*) const;	// saves image as a bitmap file
+
+			/// Saves images as a windows bitmap file
+			/// @param file_utf8 A UTF-8 string to a filename
+			void save_as_file(const char* file_utf8) const throw();
 
 			void set_color(const ::nana::color&);
 			void set_text_color(const ::nana::color&);
diff --git a/source/paint/detail/image_png.hpp b/source/paint/detail/image_png.hpp
index cab432cd..eda096e7 100644
--- a/source/paint/detail/image_png.hpp
+++ b/source/paint/detail/image_png.hpp
@@ -21,10 +21,6 @@ namespace nana
 			: public image::image_impl_interface
 		{
 		public:
-			image_png()
-			{
-			}
-
 			bool open(const nana::char_t* png_file) override
 			{
 #ifdef NANA_UNICODE
@@ -148,6 +144,12 @@ namespace nana
 				return is_opened;
 			}
 
+			bool open(const void* data, std::size_t bytes) override
+			{
+				throw std::logic_error("PNG is not supported for raw data buffer");
+				return false;
+			}
+
 			bool alpha_channel() const override
 			{
 				return pixbuf_.alpha_channel();
diff --git a/source/paint/graphics.cpp b/source/paint/graphics.cpp
index 2a997679..cba4b272 100644
--- a/source/paint/graphics.cpp
+++ b/source/paint/graphics.cpp
@@ -817,7 +817,7 @@ namespace paint
 			size_.width = size_.height = 0;
 		}
 
-		void graphics::save_as_file(const char* file) const
+		void graphics::save_as_file(const char* file_utf8) const throw()
 		{
 			if(handle_)
 			{
@@ -831,25 +831,28 @@ namespace paint
 				bmpInfo.bmiHeader.biPlanes = 1;
 				bmpInfo.bmiHeader.biBitCount = 24;
 
+				const size_t lineBytes = ((bmpInfo.bmiHeader.biWidth * 3) + 3) & (~3);
+				const size_t imageBytes = iHeight * lineBytes;
+
 				HDC hdcMem = ::CreateCompatibleDC(handle_->context);
 				BYTE *pData = nullptr;
-				HBITMAP hBmp = CreateDIBSection(hdcMem, &bmpInfo, DIB_RGB_COLORS, reinterpret_cast<void**>(&pData), 0, 0);
+				HBITMAP hBmp = ::CreateDIBSection(hdcMem, &bmpInfo, DIB_RGB_COLORS, reinterpret_cast<void**>(&pData), 0, 0);
 
 				::SelectObject(hdcMem, hBmp);
 
 				BitBlt(hdcMem, 0, 0, iWidth, iHeight, handle_->context, 0, 0, SRCCOPY);
 
-				BITMAPFILEHEADER bmFileHeader = {0};
+				BITMAPFILEHEADER bmFileHeader = { 0 };
 				bmFileHeader.bfType = 0x4d42;  //bmp
 				bmFileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
-				bmFileHeader.bfSize = bmFileHeader.bfOffBits + ((bmpInfo.bmiHeader.biWidth * bmpInfo.bmiHeader.biHeight) * 3); ///3=(24 / 8)
+				bmFileHeader.bfSize = bmFileHeader.bfOffBits + imageBytes;
 
-				HANDLE hFile = CreateFileA(file,GENERIC_WRITE,0,NULL,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);
+				HANDLE hFile = ::CreateFileW(static_cast<std::wstring>(::nana::charset(file_utf8, ::nana::unicode::utf8)).data(), GENERIC_WRITE, 0, nullptr, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
 				DWORD dwWrite = 0;
-				WriteFile(hFile,&bmFileHeader,sizeof(BITMAPFILEHEADER),&dwWrite,NULL);
-				WriteFile(hFile,&bmpInfo.bmiHeader, sizeof(BITMAPINFOHEADER),&dwWrite,NULL);
-				WriteFile(hFile,pData, iWidth * iHeight * 3,&dwWrite,NULL);
-				CloseHandle(hFile);
+				::WriteFile(hFile, &bmFileHeader, sizeof(BITMAPFILEHEADER), &dwWrite, nullptr);
+				::WriteFile(hFile, &bmpInfo.bmiHeader, sizeof(BITMAPINFOHEADER), &dwWrite, nullptr);
+				::WriteFile(hFile, pData, imageBytes, &dwWrite, nullptr);
+				::CloseHandle(hFile);
 
 				::DeleteObject(hBmp);
 				::DeleteDC(hdcMem);