In both cases the slideshows use lightbox, which is a common javascript slideshow which overlays on top of the page graying out the background, with arrows for navigation and a close button. The slideshow images are in templates/images_default and are defined here in the stylesheet:
.lb-prev:hover { background-image: url('../images_default/lightbox-prev.png'); }
.lb-next:hover { background-image: url('../images_default/lightbox-next.png'); }
.lb-data .lb-close { background-image: url('../images_default/lightbox-close.png'); }
.lb-cancel { background-image: url('../images_default/lightbox-loading.gif'); }
.lb-next:hover { background-image: url('../images_default/lightbox-next.png'); }
.lb-data .lb-close { background-image: url('../images_default/lightbox-close.png'); }
.lb-cancel { background-image: url('../images_default/lightbox-loading.gif'); }