m_pDesImg = Image::FromFile(m_csPicFileName);
Graphics g(m_pDesImg);
if ( m_signArray.GetSize() ==0)
{
IStream *pStream = NULL;
RectF rtF(0, 0, 0, 0);
m_pTmpSealImg = Image::FromStream(pStream);
g.DrawImage(m_pTmpSealImg, rtF);
}
使用gdi+的graphics（Image *）构造一个对象
IStream *pStream = NULL;
HRESULT hr = CreateStreamOnHGlobal(NULL, TRUE, &pStream);
m_pTmpSealImg = Image::FromStream(pStream);
g.DrawImage(m_pTmpSealImg, rtF);
然后把你所要画的从字节流中取出即可。