C# [GDI+] [API] Get Image bytes Length

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         Wmf       "{b96b3cad-0728-11d3-9d7b-0000f81ef32e}"
         Jpeg      "{b96b3cae-0728-11d3-9d7b-0000f81ef32e}"
         Png       "{b96b3caf-0728-11d3-9d7b-0000f81ef32e}"
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         Exif      "{b96b3cb2-0728-11d3-9d7b-0000f81ef32e}"
         PhotoCD   "{b96b3cb3-0728-11d3-9d7b-0000f81ef32e}"
         FlashPIX  "{b96b3cb4-0728-11d3-9d7b-0000f81ef32e}"
         Icon      "{b96b3cb5-0728-11d3-9d7b-0000f81ef32e}"

         static int GetImageEncoder(GpImage* image, CLSID* clsidEncoder)
         {
             int f = ;
             uint uenc = 0u, usize = 0u;
             GUID guid;
             if (GdipGetImageEncodersSize(&uenc, &usize) == )
             {
                 ImageCodecInfo* pici = (ImageCodecInfo*)LocalAlloc(0u, (void*)usize);
                 if (GdipGetImageEncoders(uenc, usize, pici) == )
                 {
                     if (GdipGetImageRawFormat(image, &guid) == )
                     {
                         for (int i = ; i < uenc; i++)
                         {
                             if (pici->FormatID == guid)
                             {
                                 *clsidEncoder = pici->Clsid;
                                 f = ;
                                 break;
                             }
                             pici++;
                         }
                     }
                 }
                 LocalFree(pici);
             }
             return f;
         }

         static int GetEncoderClsid(GUID format, CLSID* clsidEncoder)
         {
             int f = ;
             uint uenc = 0u, usize = 0u;
             if (GdipGetImageEncodersSize(&uenc, &usize) == )
             {
                 ImageCodecInfo* pici = (ImageCodecInfo*)LocalAlloc(0u, (void*)usize);
                 if (GdipGetImageEncoders(uenc, usize, pici) == )
                 {
                     for (int i = ; i < uenc; i++)
                     {
                         if (pici->FormatID == format)
                         {
                             *clsidEncoder = pici->Clsid;
                             f = ;
                             break;
                         }
                         pici++;
                     }
                 }
                 GlobalFree(pici);
             }
             return f;
         }

 　　　　　static int GetEncoderClsid(string format, CLSID* clsidEncoder)
         {
             int f = ;
             uint uenc = 0u, usize = 0u;
             ushort* psz = _L(format);
             if (GdipGetImageEncodersSize(&uenc, &usize) == )
             {
                 ImageCodecInfo* pici = (ImageCodecInfo*)LocalAlloc(0u, (void*)usize);
                 if (GdipGetImageEncoders(uenc, usize, pici) == )
                 {
                     for (int i = ; i < uenc; i++)
                     {
                         if (lstrcmpW(pici->MimeType, psz) == )
                         {
                             *clsidEncoder = pici->Clsid;
                             f = ;
                             break;
                         }
                         pici++;
                     }
                 }
                 GlobalFree(pici);
             }
             _Lr(psz);
             return f;
         }

         static int GetImageLength(GpImage* image, GUID format, void** usize)
         {
             int f = ;
             CLSID clsid;
             if (GetEncoderClsid(format, &clsid) != )
             {
                 void* hgbl = GlobalAlloc(GMEM_MOVEABLE, null);
                 void* pstm;
                 if (SUCCEEDED(CreateStreamOnHGlobal(hgbl, , &pstm)))
                 {
                     if (GdipSaveImageToStream(image, pstm, &clsid, null) == )
                     {
                         *usize = GlobalSize(hgbl);
                         f = ;
                     }
                     //Marshal.Release((IntPtr)pstm);
                 }
                 GlobalFree(hgbl);
             }
             return f;
         }

         static int GetImageLength(GpImage* image, string format, void** usize)
         {
             int f = ;
             CLSID clsid;
             if (GetEncoderClsid(format, &clsid) != )
             {
                 void* hgbl = GlobalAlloc(GMEM_MOVEABLE, null);
                 void* pstm;
                 if (SUCCEEDED(CreateStreamOnHGlobal(hgbl, , &pstm)))
                 {
                     if (GdipSaveImageToStream(image, pstm, &clsid, null) == )
                     {
                         *usize = GlobalSize(hgbl);
                         f = ;
                     }
                     //Marshal.Release((IntPtr)pstm);
                 }
                 GlobalFree(hgbl);
             }
             return f;
         }

 //invoke:
     GpImage* image;
     uint usize;
     /*
        ...
        Create or Load Image
        ...
      */
     GetImageLength(image, "image/jpeg", &usize);