procedure TForm1.Button1Click(Sender: TObject); var i:integer; begin for i:=0 to FileListBox1.items.count-1 do begin FileListBox1.itemindex:=i; // do your stuff here, eg image1.canvas.picture.loadfromfile(FileListBox1.filename); .. Application.processmessages; // makes the processing visible end; // for loop GoBtn.caption:='done'; // show the processing finished end;