shared DLL VS static Link, Are they different?

hi, everyone, I meet a strange problem:
I'm using VC6 and create a dialog based applications. And I want to add
a third part library( Open computer library--OpenCV AS DLL). I linked
with the cxcored.lib. My APP will call functions in cxcore001d.dll.

I only add two functions in the OnInitDialog function:
/////////////////////////////////////////////////////////////////
BOOL COpenCVdialogDlg::OnInitDialog()
{
     ......
     m_iplImage = cvCreateImage(ImgSize,IPL_DEPTH_8U,IMAGE_CHANNELS);
     cvReleaseImage(&m_iplImage);
     ......
}
////////////////////////////////////////////////////////////////
In the code above, I only create an Image and release it quickly, which
seems I do Nothing. ^_^ ,The two functions are exported from
cxcore100d.dll( associated with cxcored.lib)

Here comes my problem. When I build the APP with static MFC library, the
program works fine. But When I build the APP with "Using MFC as shared
DLL" option, there are many memory leak report when I exit the APP.

It is very strange that "using MFC as shared DLL" and "using MFC as a
static library" are much different? Otherwise, There are something wrong
  with the source code generating cxcore100d.dll?

By the way, OpenCV is an open source library,so, I have the full source
code of "cxcore100d.dll" , I examine the code and can't find anything wrong.
Here is its DLL Main entry:
////////////////////////////////////////////////////////////////
#if defined WIN32 || defined WIN64
BOOL WINAPI DllMain( HINSTANCE, DWORD fdwReason, LPVOID )
{
     CvContext *pContext;

     switch (fdwReason)
     {
     case DLL_PROCESS_ATTACH:
         g_TlsIndex = TlsAlloc();
         if( g_TlsIndex == TLS_OUT_OF_INDEXES ) return FALSE;
         //break;

     case DLL_THREAD_ATTACH:
         pContext = icvCreateContext();
         if( pContext == NULL)
             return FALSE;
         TlsSetValue( g_TlsIndex, (LPVOID)pContext );
         break;

     case DLL_THREAD_DETACH:
         if( g_TlsIndex != TLS_OUT_OF_INDEXES )
         {
             pContext = (CvContext*)TlsGetValue( g_TlsIndex );
             if( pContext != NULL )
                 icvDestroyContext( pContext );
         }
         break;

     case DLL_PROCESS_DETACH:
         if( g_TlsIndex != TLS_OUT_OF_INDEXES )
         {
             pContext = (CvContext*)TlsGetValue( g_TlsIndex );
             if( pContext != NULL )
                 icvDestroyContext( pContext );
         }
         TlsFree( g_TlsIndex );
         break;
     default:
         ;
     }
     return TRUE;
}
////////////////////////////////////////////////////////////////
I was confused that why the "break" statement is commented after the
"case DLL_PROCESS_ATTACH:"?

Further more, the cvCreateImage and cvReleaseImage function in my APP is
   regularly simple, they only allocate a piece of memory and delete it.

Thanks for reading my Post!