WordPress started in 2003 with a single bit of code to enhance the typography of everyday writing and with fewer users than you can count on your fingers and toes. Since then it has grown to be the largest self-hosted blogging tool in the world, used on millions of sites and seen by tens of millions of people every day.
We can use featured image as lightbox image from Post Custom Fields. It is flexible and easyly.
We can use featured image as a lightbox video. (youtube and vimeo) can be embeded.
We can use featured image as a internal page link or a external link. it is easy.
We can use featured image as lightbox content. write your custom any HTML code or Video Embed Codes (youtube,vime,daylimotion,google,yahoo, etc) or IFRAME supported.