用流存储图象，在access数据库中，出现错误高手指点一下这该怎么办？

Question

错误是：stack overflow 
 var
  strm:tmemorystream;
  ext:string;
begin
    dm.materialcds.append;
strm:=tmemorystream.Create;
    if image1.picture.Graphic <> nil then
    begin
       ext:=extractfileext(openpicturedialog1.FileName ); //取出文件的扩展名
       image1.Picture.Graphic.SaveToStream(strm);
       strm.Position :=0;
       tblobfield(dm.MaterialCDS.FieldByName('图片')).LoadFromStream(strm);
        if uppercase(ext) = '.BMP' then
        dm.MaterialCDS.FieldByName('isbmp').Value := 1
        else if (uppercase(ext) = '.JPG') OR ( uppercase(ext) = '.JPEG') Then
            dm.MaterialCDS.FieldByName('isbmp').Value := 0;
      end;
      dm.MaterialCDS.ApplyUpdates(0);
      strm.Free;
end;
读图片
  var
  strm:tadoblobstream;
  jpegimage:tjpegimage;
  bitmap:tbitmap;
strm := tadoblobstream.Create(tblobfield(dm.severADOQ1.FieldByName('图片')),bmread);
   try //try1
    //strm.position :=0;
    xzcailiaoform.image1.Picture.Graphic := nil;
    if dm.MaterialCDS.FieldByName('isbmp').AsString ='1' then //BMP型图像数据
    begin //begin11
      bitmap := tbitmap.Create ;
      try //try11
        bitmap.LoadFromStream(strm);
        xzcailiaoform.image1.Picture.Graphic := bitmap;
      finally
        bitmap.Free;
      end; //end try11
      end
      else if dm.severADOQ1.FieldByName('isbmp').asstring ='0' then //JPEG型图像数据
      begin //begin12
        jpegimage := tjpegimage.Create ;
      try //try12
        jpegimage.LoadFromStream(strm);
        xzcailiaoform.image1.Picture.Graphic := jpegimage;
      finally
        jpegimage.Free ;
      end; //end try12
      end; //end begin12
      finally
      strm.Free ;
    end; //end try1
错误是：stack overflow

Answer 1

stream:=TMemoryStream.Create;
image1.Picture.Graphic.SaveToStream(stream);
adoquery1.Insert;
TBlobField(adoQuery1.FieldByName('insertpic')).loadfromstream(stream);
adoQuery1.post;

Answer 2

这是上传:
  query:=TADOQuery.Create(nil);
  query.Connection:=frmmain.ADOConnection1;
  query.Close();
  query.SQL.Add('SELECT  * FROM jb700 where PERSONID='+quotedstr(trim(staffid)));
  query.Open();
    query.Edit();
    stream:=TmemoryStream.Create();
    stream.LoadFromFile(FileDIR+'tmp\'+staffid+'.jpeg');
    TBlobField(query.FieldByName('photo')).LoadFromStream(stream);
    query.Post();
    query.Close();
    FreeAndNil(stream);
    FreeAndNil(query);
    msgbox('图片保存成功!!!');这是下载:
if trim(vartostr(query.FieldByName('photo'AsVariant))<>'' then
 begin
   TBlobField(query.FieldByName('photo')).SaveToFile(filename);
end;