// 加载bmp文件到CBitmap
bool LoadBmpPic(CString strBmpPath, CBitmap&bmp)
{
	HBITMAP  bitmap;

	try
	{
		bmp.Detach();
		//从文件路径加载图片
		bitmap = (HBITMAP)::LoadImage(NULL, strBmpPath, IMAGE_BITMAP, 0, 0,
			LR_CREATEDIBSECTION | LR_LOADFROMFILE | LR_DEFAULTSIZE);

		if (bmp.Attach(bitmap))
		{
			return true;
		}
	}
	catch (...)
	{
		AfxMessageBox("LoadBmpPic catch!");
		return false;
	}
	return true;
}

png转CBitmap:
void LoadPngImageToBmp(CString& path, CBitmap* bm)
{
	CImage img; 
	img.Load(path);
#if 0
	HBITMAP hbmp = (HBITMAP)img.operator HBITMAP();
	bm->DeleteObject();
	bm->Attach(hbmp);
#elif 1
	bm->Attach(img.Detach());
#else
	HBITMAP hBitmap;
	hBitmap = img.Detach();
	bm->Attach(hBitmap);
#endif
}