Open A image When the site loads How to open a image when the site loads like in this site. Can this be done wtih lightbox or colorbox
You can use Splashify module for this


  Display a splash page anywhere on your site by redirecting the user, showing a lightbox, or displaying a popup. This module is designed to be search engine friendly, mobile device friendly and offers multiple configuration options.


Otherwise you can try with lightbox and custom scripts an example is given here