A question regarding direct links of images and ads

Hello there. I am quite new to php, but not as much to css. Been playing around a lot with wordpress in the last few months and I got almost everything I tried and experimented with, working. But I really need help with this one.

I saw a couple of web pages using a smart ad placement when the user that is browsing the blog clicks on a screenshot/image link. He gets a fullscreen view of the image, resizing it to whatever size the browser window is, and also an ad placement on top.

What is the trick on accomplishing this ? This blog for example is using lazyest gallery and nggallery, and when you click a screenshot for example – https://www.gamesteady.com/gallery/half-life-2/half-life-2-screenshots_30.jpg – you get the idea.

I really want to implement this on my blog before launching it.

Would really appreciate if someone points me to a solution so I can start working on right away.

Thank you for the time you took to read this, and thanks a million in advance.