IImage*来自IBitmap图像*

int Rescale(const UBitmap* src, UBitmap* dst, UINT w, UINT h)

// Get the IImage ptr from the source

HRESULT hr;
CoInitializeEx(NULL, COINIT_MULTITHREADED);

IImage* img_in = src->GetIImage();

if (img_in)
{
    IImagingFactory* pImgf = NULL;
    hr = CoCreateInstance(CLSID_ImagingFactory, 0, CLSCTX_ALL,
            IID_IImagingFactory, void**)&pImgf);

    assert(SUCCEEDED(hr));
        IBitmapImage* pIResBmp = NULL;
        hr = pImgf->CreateBitmapFromImage(img_in,w,h, PixelFormatDontCare, 
                 InterpolationHintBilinear, &pIResBmp);
    assert(SUCCEEDED(hr));

    IImage* pImgOut = NULL;  // How to obtain IImage pointer from pIResBmp?

    bmpOut = new UBitmap(dst);
    pImgf->Release();
}   

CoUninitialize();