don't use implicit wxString->char*/wchar_t* conversion, it will not be available in wxUSE_STL build in the future

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@46391 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/image.cpp

@@ -2231,7 +2231,7 @@ bool wxImage::LoadFile( wxInputStream& stream, const wxString& mimetype, int ind
 
     if (stream.IsSeekable() && !handler->CanRead(stream))
     {
-        wxLogError(_("Image file is not of type %s."), (const wxChar*) mimetype);
+        wxLogError(_("Image file is not of type %s."), mimetype);
         return false;
     }
     else