MFC，VC++重叠贴图，先贴正常图片，再贴透明PNG图片

    CRect   rectP;
	m_picture.GetClientRect(&rectP);
	CDC *pDC = m_picture.GetDC();
	CImage ImageBottom, ImageTop;
	ImageBottom.Load(_T("../Res/444.bmp"));
	ImageBottom.Draw(pDC->m_hDC, 0, 0, rectP.Width(), rectP.Height(), 0, 0,                        ImageBottom.GetWidth(), ImageBottom.GetHeight());
	ImageBottom.Destroy();

	ImageTop.Load(_T("../Res/国旗.png"));
	if (ImageTop.IsNull())
	{
		MessageBox(_T("没加载成功"));
		return -1;
	}
	if (ImageTop.GetBPP() == 32) //确认该图像包含Alpha通道
	{
		int i;
		int j;
		for (i = 0; i < ImageTop.GetWidth(); i++)
		{
			for (j = 0; j < ImageTop.GetHeight(); j++)
			{
				byte *pByte = (byte *)ImageTop.GetPixelAddress(i, j);
				pByte[0] = pByte[0] * pByte[3] / 255;
				pByte[1] = pByte[1] * pByte[3] / 255;
				pByte[2] = pByte[2] * pByte[3] / 255;
			}
		}
	}
	ImageTop.Draw(pDC->m_hDC, 0, 0, rectP.Width(), rectP.Height(), 0, 0, ImageTop.GetWidth(), ImageTop.GetHeight());
	ImageTop.Destroy();
	ReleaseDC(pDC);

废话不多说，直接上代码，亲测可用：如图，底图为bitmap，国旗为透明背景png