HBITMAP StretchBlt caused image saturation

Question

I used the following code to resize win32 HBITMAP.

HBITMAP ResizeBitmap(HDC hDC, HBITMAP source)
{
    HDC hMemDC2 = CreateCompatibleDC(hDC);
    HGDIOBJ hOld2 = SelectObject(hMemDC2, source);

    BITMAP bitmap = { 0 };
    GetObject(hBitmap, sizeof(BITMAP), &bitmap);

    float SCALE = IMAGE_SCALE;
    int nWidth = (int)ceil(bitmap.bmWidth / SCALE / 32) * 32;
    int nHeight = (int)ceil(bitmap.bmHeight / SCALE / 32) * 32;
    int dWidth = (int)round(bitmap.bmWidth / SCALE);
    int dHeight = (int)round(bitmap.bmHeight / SCALE);

    HDC hMemDC1 = CreateCompatibleDC(hDC);
    HBITMAP hBitmap1 = CreateCompatibleBitmap(hDC, nWidth, nHeight);
    HGDIOBJ hOld1 = SelectObject(hMemDC1, hBitmap1);

    StretchBlt(hMemDC1, 0, 0, dWidth, dHeight, hMemDC2, 0, 0, bitmap.bmWidth, bitmap.bmHeight, SRCCOPY);

    SelectObject(hMemDC1, hOld1);
    SelectObject(hMemDC2, hOld2);
    DeleteDC(hMemDC1);
    DeleteDC(hMemDC2);

    return hBitmap1;
}

However, I found the new image was saturated. As show bellow the original image

And the new image (Please ignore the green rectangle in the image)

Why?