How To Create An Image Gallery That Opens On The Same Screen

[smoove8]

Hi, I'm in no way affiliated to this site but I recently saw a submission in the forum posts telling people to review it. I'm trying to create the same effect as him. When you click on an image on the right, the image will appear in the center without refreshing the screen. I think this looks awesome, but I'm having trouble finding the info on how to do it. Can anyone help me out? Maybe a past post?

http://www.captivision.co.uk/gallery.html