Code
StreamPtr     pStm;  
                    pStm.CreateInstance("ADODB.Stream");  
                    variant_t   varOptional(DISP_E_PARAMNOTFOUND,VT_ERROR);  
                    pStm->PutType(adTypeBinary);//类型为二进制  
                    //得到字段内容的大小  
                    long   lDataSize   =   m_pRecordset->GetFields()->GetItem("photo")->ActualSize;  
                  //m_pRecordset为一个打开的纪录集对象，含有photo这个blob字段  
                  pStm->Open(   varOptional,      
                                            adModeUnknown,   adOpenStreamUnspecified,   _bstr_t(),   _bstr_t());                    
                    //打开pStm  
                      pStm->Write(_variant_t(m_pRecordset->GetFields()->GetItem("photo")->Value));  
                      //把photo字段的内容写入pStm  
                      pStm->SaveToFile("c:\\publogo.jpg",   adSaveCreateOverWrite);  
                      pStm->Close();  
                        //直接保存为文件,如果是别的格式只要保存的时候改变后缀就可以了  
                下面是如果不保存成文件可以直接通过Com对象来绘制该图片，IPicture   可以显示多种格式图片.  
                  HGLOBAL   hGlobal   =   GlobalAlloc(GMEM_MOVEABLE,   pStm->GetSize());      
                  LPVOID   pvData   =   NULL;      
                IStream   *ps;  
                  if   (hGlobal   !=   NULL)      
                {      
                                      if   ((pvData   =   GlobalLock(hGlobal))   !=   NULL)      
                                    {      
                                                  char   *   m_pBMPBuffer   =   new   char[pStm->GetSize()+1];//分配必要的存储空间  
                                                  char   *pBuf   =   NULL;  
                                                    SafeArrayAccessData(varBLOB.parray,(void   **)&pBuf);  
                                                    memcpy(pvData,pBuf,pStm->GetSize());   //复制数据到缓冲   区                       m_pBMPBuffer  
                                              SafeArrayUnaccessData   (varBLOB.parray);  
                                            GlobalUnlock(hGlobal);  
                                            CreateStreamOnHGlobal(hGlobal,   TRUE,   &ps);  
                                        }  
                  }  
   
                IPicture   *pPic;    
                  if(SUCCEEDED(OleLoadPicture(ps,pStm->GetSize()   ,TRUE,IID_IPicture,(LPVOID*)&pPic)))    
                  {    
   
                        OLE_XSIZE_HIMETRIC   hmWidth;      
                        OLE_YSIZE_HIMETRIC   hmHeight;      
                        pPic->get_Width(&hmWidth);      
                        pPic->get_Height(&hmHeight);      
                        double   fX,fY;      
                        CDC   *pDC   =   GetClientDC();//这里根据具体请况来取  
                    fX=(double)pDC->GetDeviceCaps(HORZRES)*(double)hmWidth/((double)pDC->GetDeviceCaps(HORZSIZE)*100.0);      
  fY   =(double)pDC->GetDeviceCaps(VERTRES)*(double)hmHeight/((double)pDC->GetDeviceCaps(VERTSIZE)*100.0);      
              if(FAILED(pPic->Render(*pDC,0,0,(DWORD)fX,(DWORD)fY,0,hmHeight,hmWidth,-hmHeight,NULL)))      
                    AfxMessageBox("图像绘制失败！");        
                pPic->Release();      
  }      
                      这样就完成了对图片文件从数据库读出和显示的过程。  
                    对于从文件写入数据库就相对的容易多了,  
                      _StreamPtr     pStm;  
                    pStm.CreateInstance("ADODB.Stream");  
                    variant_t   varOptional(DISP_E_PARAMNOTFOUND,VT_ERROR);  
                    long   lDataSize   =   m_pRecordset->GetFields()->GetItem("photo")->ActualSize;  
                    pStm->PutType(adTypeBinary；  
   
                  pStm->Open(   varOptional,      
                                            adModeUnknown,   adOpenStreamUnspecified,   _bstr_t(),   _bstr_t());  
                    pStm->LoadFromFile("c:\\book.gif");//读入文件  
                    variant_t     varBLOB=pStm->Read(adReadAll);  
                m_pRecordset->GetFields()->GetItem("photo")->Value=   varBLOB;//保存到数据集对象。