var banner = new Array();

banner[0]='https://i238.photobucket.com/albums/ff200/adarocas/bleachfan/Imagen-1.jpg';
banner[1]='https://i238.photobucket.com/albums/ff200/adarocas/bleachfan/Imagen-2.jpg';
banner[2]='https://i238.photobucket.com/albums/ff200/adarocas/bleachfan/Imagen-3.jpg';
banner[3]='https://i238.photobucket.com/albums/ff200/adarocas/bleachfan/Imagen-4.jpg';

document.getElementById('i_logo').src= banner[Math.floor(Math.random()*banner.length)];