CControlUI* pCtrl=NULL;
CDuiString sCtrlKey = _T(“your_key_name”);
HBITMAP hBmp; // GDI方式获得图片句柄

if(pCtrl)
{	
	m_PaintManager.RemoveImage(sCtrlKey);	
	m_PaintManager.AddImage(sCtrlKey, hBmp, w, h, false);		
	pCtrl->SetBkImage(sCtrlKey);
}

参考：https://blog.csdn.net/taquguodedifang/article/details/72809215