This will place a TImage object on the form and fill it with a picture.

uses ExtCtrls;
procedure TForm1.Button1Click(Sender: TObject);
var
  ti: tImage;
begin
  ti := tImage.create(self);
with ti do
begin
  parent := self;
  autosize := true;
  Picture.LoadFromFile('c:\windows\MyBmp.bmp');
  show;
end;
end;

To make it always fit the window, do it this way:

with ti do
begin
  align := alClient;
  stretch := true;
  autosize := true;
end;