如何往数据库存取jpg图片，望指教

Question

注：是jpg,不是bmp

Answer 1

这里有两个过程，是显示和保存图片的。数据库是access，参数调用如下。
showpicture(image3, Dm1.ADOQ_zyryjbqk, 'zp');
savepicture(image1, Dm1.ADOQ_qyjbqk, 'yyzzsmj');
第一个是image的名字，第二个是数据源，第三个是存图片字段名。
请参考。procedure showpicture(img: Timage; ADOQ: TADOQuery; field: string);
var MS: Tmemorystream;
begin
  if not ADOQ.FieldByName(field).isnull then
    begin
      MS := TMemoryStream.Create;
      try
        TBlobField(ADOQ.FieldByName(field)).SaveToStream(MS);
        MS.Position := 0; //注意
        try
          img.Picture.Graphic.LoadFromStream(MS);
        except
          //如果格式无效，则显示默认图片
          on EInvalidGraphic do
          //img.Picture.Graphic := fmain.Image4.Picture.Graphic;
        end;
      finally
        MS.Free;
      end;
    end
  else
    begin
      MS := TMemoryStream.Create;
      try
        fmain.Image4.Picture.Graphic.SaveToStream(MS);
        MS.Position := 0; //注意
        img.Picture.Graphic.LoadFromStream(MS);
      finally
        MS.Free;
      end;
    end;
end;procedure savepicture(img: Timage; ADOQ: TADOQuery; field: string);
var photo: Tmemorystream;
begin
   photo := Tmemorystream.create;
   img.Picture.graphic.savetoStream(photo);
   Tblobfield(ADOQ.FieldByName(field)).loadfromstream(photo);
   photo.Clear;
end;

Answer 2

procedure TForm1.btnLoadImageClick(Sender: TObject);
var
  sFileName : string;  function BlobContentToString(const AFileName : string) : string;
  begin
    with TFileStream.Create(AFileName, fmOpenRead) do
    try
      SetLength(Result, Size);
      Read(Pointer(Result)^, Size);
    finally
      Free;
    end;
  end;begin
  if OpenDialog1.Execute then
  begin
    sFileName := OpenDialog1.FileName;
    with ADOTable1 do
    begin
      Open;
      Insert;
      FieldByName('Name').AsString := Edit1.Text;
      FieldByName('Photo').AsString := BlobContentToString(sFileName);
      Post;
    end;
  end;
end;procedure TForm1.btnShowClick(Sender: TObject);
var
  BS : TADOBlobStream;
  JpegImage : TJpegImage;
  sFileName : string;
begin
  JpegImage := TJpegImage.Create;
  BS := TADOBlobStream.Create(TBlobField(ADOTable1.FieldByName('Photo')), bmRead);
  try
    JpegImage.LoadFromStream(BS);
    Image1.Picture.Assign(JpegImage);
    sFileName := ExtractFilePath(Application.ExeName) + 'tmpBlob';
    sFileName := sFileName + '.jpg';
    BS.SaveToFile(sFileName);
    //OleContainer1.CreateObjectFromFile(sFileName, False);
    //Image1 := TImage.Create(Self);
    //Image1.Picture.Graphic.LoadFromStream(BS);
  finally
    JpegImage.Free;
    BS.Free;
  end;
end;