Load Bitmap Drag&Drop

uses ShellApi

private
    { Private-Deklarationen }
    originalPanelWindowProc : TWndMethod;
      procedure PanelWindowProc (var Msg : TMessage) ;
      procedure PanelImageDrop (var Msg : TWMDROPFILES) ;
      
//

procedure TForm1.PanelWindowProc(var Msg: TMessage) ;
begin
    if Msg.Msg = WM_DROPFILES then
      PanelImageDrop(TWMDROPFILES(Msg))
    else
      originalPanelWindowProc(Msg) ;
end;

procedure TForm1.PanelImageDrop(var Msg: TWMDROPFILES) ;
var
    numFiles : longInt;
    buffer : array[0..MAX_PATH] of char;
begin
    numFiles := DragQueryFile(Msg.Drop, $FFFFFFFF, nil, 0) ;
    if numFiles > 1 then
    begin
      ShowMessage('You can drop only one image file at a time!') ;
    end
    else
    begin
      DragQueryFile(Msg.Drop, 0, @buffer, sizeof(buffer)) ;
      try
        Image1.Picture.LoadFromFile(buffer) ;
      except
        on EInvalidGraphic do ShowMessage('Unsupported image file, or not an image!') ;
      end;
    end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  originalPanelWindowProc := Panel1.WindowProc;
    Panel1.WindowProc := PanelWindowProc;

    DragAcceptFiles(Panel1.Handle,true) ;
end;