Me parece que esto lo hace con jquery aca esta el código que usa
Código Javascript :
jQuery(function($) {
$.supersized({
//Functionality
slideshow: 1, //Slideshow on/off
autoplay: 1, //Slideshow starts playing automatically
start_slide: 1, //Start slide (0 is random)
random: 0, //Randomize slide order (Ignores start slide)
slide_interval: 6000, //Length between transitions
transition: 1, //0-None, 1-Fade, 2-Slide Top, 3-Slide Right, 4-Slide Bottom, 5-Slide Left, 6-Carousel Right, 7-Carousel Left
transition_speed: 1500, //Speed of transition
new_window: 1, //Image links open in new window/tab
pause_hover: 0, //Pause slideshow on hover
keyboard_nav: 1, //Keyboard navigation on/off
performance: 1, //0-Normal, 1-Hybrid speed/quality, 2-Optimizes image quality, 3-Optimizes transition speed // (Only works for Firefox/IE, not Webkit)
image_protect: 1, //Disables image dragging and right click with Javascript
image_path: 'img/', //Default image path
//Size & Position
min_width: 0, //Min width allowed (in pixels)
min_height: 0, //Min height allowed (in pixels)
vertical_center: 1, //Vertically center background
horizontal_center: 1, //Horizontally center background
fit_portrait: 1, //Portrait images will not exceed browser height
fit_landscape: 0, //Landscape images will not exceed browser width
//Components
navigation: 1, //Slideshow controls on/off
thumbnail_navigation: 1, //Thumbnail navigation
slide_counter: 1, //Display slide numbers
slide_captions: 1, //Slide caption (Pull from "title" in slides array)
slides: [ //Slideshow Images
{image: 'fondos/bground1.jpg'},
{image: 'fondos/bground2.jpg'},
{image: 'fondos/bground3.jpg'},
{image: 'fondos/bground4.jpg'},
{image: 'fondos/bground5.jpg'}
]
});
});
Esta claro donde debes poner los enlaces de las imágenes